Commit Graph

2171 Commits

Author SHA1 Message Date
Linus Torvalds
7d4e49a77d - The 3 patch series "hung_task: extend blocking task stacktrace dump to
semaphore" from Lance Yang enhances the hung task detector.  The
   detector presently dumps the blocking tasks's stack when it is blocked
   on a mutex.  Lance's series extends this to semaphores.
 
 - The 2 patch series "nilfs2: improve sanity checks in dirty state
   propagation" from Wentao Liang addresses a couple of minor flaws in
   nilfs2.
 
 - The 2 patch series "scripts/gdb: Fixes related to lx_per_cpu()" from
   Illia Ostapyshyn fixes a couple of issues in the gdb scripts.
 
 - The 9 patch series "Support kdump with LUKS encryption by reusing LUKS
   volume keys" from Coiby Xu addresses a usability problem with kdump.
   When the dump device is LUKS-encrypted, the kdump kernel may not have
   the keys to the encrypted filesystem.  A full writeup of this is in the
   series [0/N] cover letter.
 
 - The 2 patch series "sysfs: add counters for lockups and stalls" from
   Max Kellermann adds /sys/kernel/hardlockup_count and
   /sys/kernel/hardlockup_count and /sys/kernel/rcu_stall_count.
 
 - The 3 patch series "fork: Page operation cleanups in the fork code"
   from Pasha Tatashin implements a number of code cleanups in fork.c.
 
 - The 3 patch series "scripts/gdb/symbols: determine KASLR offset on
   s390 during early boot" from Ilya Leoshkevich fixes some s390 issues in
   the gdb scripts.
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Merge tag 'mm-nonmm-stable-2025-05-31-15-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - "hung_task: extend blocking task stacktrace dump to semaphore" from
   Lance Yang enhances the hung task detector.

   The detector presently dumps the blocking tasks's stack when it is
   blocked on a mutex. Lance's series extends this to semaphores

 - "nilfs2: improve sanity checks in dirty state propagation" from
   Wentao Liang addresses a couple of minor flaws in nilfs2

 - "scripts/gdb: Fixes related to lx_per_cpu()" from Illia Ostapyshyn
   fixes a couple of issues in the gdb scripts

 - "Support kdump with LUKS encryption by reusing LUKS volume keys" from
   Coiby Xu addresses a usability problem with kdump.

   When the dump device is LUKS-encrypted, the kdump kernel may not have
   the keys to the encrypted filesystem. A full writeup of this is in
   the series [0/N] cover letter

 - "sysfs: add counters for lockups and stalls" from Max Kellermann adds
   /sys/kernel/hardlockup_count and /sys/kernel/hardlockup_count and
   /sys/kernel/rcu_stall_count

 - "fork: Page operation cleanups in the fork code" from Pasha Tatashin
   implements a number of code cleanups in fork.c

 - "scripts/gdb/symbols: determine KASLR offset on s390 during early
   boot" from Ilya Leoshkevich fixes some s390 issues in the gdb
   scripts

* tag 'mm-nonmm-stable-2025-05-31-15-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (67 commits)
  llist: make llist_add_batch() a static inline
  delayacct: remove redundant code and adjust indentation
  squashfs: add optional full compressed block caching
  crash_dump, nvme: select CONFIGFS_FS as built-in
  scripts/gdb/symbols: determine KASLR offset on s390 during early boot
  scripts/gdb/symbols: factor out pagination_off()
  scripts/gdb/symbols: factor out get_vmlinux()
  kernel/panic.c: format kernel-doc comments
  mailmap: update and consolidate Casey Connolly's name and email
  nilfs2: remove wbc->for_reclaim handling
  fork: define a local GFP_VMAP_STACK
  fork: check charging success before zeroing stack
  fork: clean-up naming of vm_stack/vm_struct variables in vmap stacks code
  fork: clean-up ifdef logic around stack allocation
  kernel/rcu/tree_stall: add /sys/kernel/rcu_stall_count
  kernel/watchdog: add /sys/kernel/{hard,soft}lockup_count
  x86/crash: make the page that stores the dm crypt keys inaccessible
  x86/crash: pass dm crypt keys to kdump kernel
  Revert "x86/mm: Remove unused __set_memory_prot()"
  crash_dump: retrieve dm crypt keys in kdump kernel
  ...
2025-05-31 19:12:53 -07:00
Linus Torvalds
1b98f357da Networking changes for 6.16.
Core
 ----
 
  - Implement the Device Memory TCP transmit path, allowing zero-copy
    data transmission on top of TCP from e.g. GPU memory to the wire.
 
  - Move all the IPv6 routing tables management outside the RTNL scope,
    under its own lock and RCU. The route control path is now 3x times
    faster.
 
  - Convert queue related netlink ops to instance lock, reducing
    again the scope of the RTNL lock. This improves the control plane
    scalability.
 
  - Refactor the software crc32c implementation, removing unneeded
    abstraction layers and improving significantly the related
    micro-benchmarks.
 
  - Optimize the GRO engine for UDP-tunneled traffic, for a 10%
    performance improvement in related stream tests.
 
  - Cover more per-CPU storage with local nested BH locking; this is a
    prep work to remove the current per-CPU lock in local_bh_disable()
    on PREMPT_RT.
 
  - Introduce and use nlmsg_payload helper, combining buffer bounds
    verification with accessing payload carried by netlink messages.
 
 Netfilter
 ---------
 
  - Rewrite the procfs conntrack table implementation, improving
    considerably the dump performance. A lot of user-space tools
    still use this interface.
 
  - Implement support for wildcard netdevice in netdev basechain
    and flowtables.
 
  - Integrate conntrack information into nft trace infrastructure.
 
  - Export set count and backend name to userspace, for better
    introspection.
 
 BPF
 ---
 
  - BPF qdisc support: BPF-qdisc can be implemented with BPF struct_ops
    programs and can be controlled in similar way to traditional qdiscs
    using the "tc qdisc" command.
 
  - Refactor the UDP socket iterator, addressing long standing issues
    WRT duplicate hits or missed sockets.
 
 Protocols
 ---------
 
  - Improve TCP receive buffer auto-tuning and increase the default
    upper bound for the receive buffer; overall this improves the single
    flow maximum thoughput on 200Gbs link by over 60%.
 
  - Add AFS GSSAPI security class to AF_RXRPC; it provides transport
    security for connections to the AFS fileserver and VL server.
 
  - Improve TCP multipath routing, so that the sources address always
    matches the nexthop device.
 
  - Introduce SO_PASSRIGHTS for AF_UNIX, to allow disabling SCM_RIGHTS,
    and thus preventing DoS caused by passing around problematic FDs.
 
  - Retire DCCP socket. DCCP only receives updates for bugs, and major
    distros disable it by default. Its removal allows for better
    organisation of TCP fields to reduce the number of cache lines hit
    in the fast path.
 
  - Extend TCP drop-reason support to cover PAWS checks.
 
 Driver API
 ----------
 
  - Reorganize PTP ioctl flag support to require an explicit opt-in for
    the drivers, avoiding the problem of drivers not rejecting new
    unsupported flags.
 
  - Converted several device drivers to timestamping APIs.
 
  - Introduce per-PHY ethtool dump helpers, improving the support for
    dump operations targeting PHYs.
 
 Tests and tooling
 -----------------
 
  - Add support for classic netlink in user space C codegen, so that
    ynl-c can now read, create and modify links, routes addresses and
    qdisc layer configuration.
 
  - Add ynl sub-types for binary attributes, allowing ynl-c to output
    known struct instead of raw binary data, clarifying the classic
    netlink output.
 
  - Extend MPTCP selftests to improve the code-coverage.
 
  - Add tests for XDP tail adjustment in AF_XDP.
 
 New hardware / drivers
 ----------------------
 
  - OpenVPN virtual driver: offload OpenVPN data channels processing
    to the kernel-space, increasing the data transfer throughput WRT
    the user-space implementation.
 
  - Renesas glue driver for the gigabit ethernet RZ/V2H(P) SoC.
 
  - Broadcom asp-v3.0 ethernet driver.
 
  - AMD Renoir ethernet device.
 
  - ReakTek MT9888 2.5G ethernet PHY driver.
 
  - Aeonsemi 10G C45 PHYs driver.
 
 Drivers
 -------
 
  - Ethernet high-speed NICs:
    - nVidia/Mellanox (mlx5):
      - refactor the stearing table handling to reduce significantly
        the amount of memory used
      - add support for complex matches in H/W flow steering
      - improve flow streeing error handling
      - convert to netdev instance locking
    - Intel (100G, ice, igb, ixgbe, idpf):
      - ice: add switchdev support for LLDP traffic over VF
      - ixgbe: add firmware manipulation and regions devlink support
      - igb: introduce support for frame transmission premption
      - igb: adds persistent NAPI configuration
      - idpf: introduce RDMA support
      - idpf: add initial PTP support
    - Meta (fbnic):
      - extend hardware stats coverage
      - add devlink dev flash support
    - Broadcom (bnxt):
      - add support for RX-side device memory TCP
    - Wangxun (txgbe):
      - implement support for udp tunnel offload
      - complete PTP and SRIOV support for AML 25G/10G devices
 
  - Ethernet NICs embedded and virtual:
    - Google (gve):
      - add device memory TCP TX support
    - Amazon (ena):
      - support persistent per-NAPI config
    - Airoha:
      - add H/W support for L2 traffic offload
      - add per flow stats for flow offloading
    - RealTek (rtl8211): add support for WoL magic packet
    - Synopsys (stmmac):
      - dwmac-socfpga 1000BaseX support
      - add Loongson-2K3000 support
      - introduce support for hardware-accelerated VLAN stripping
    - Broadcom (bcmgenet):
      - expose more H/W stats
    - Freescale (enetc, dpaa2-eth):
      - enetc: add MAC filter, VLAN filter RSS and loopback support
      - dpaa2-eth: convert to H/W timestamping APIs
    - vxlan: convert FDB table to rhashtable, for better scalabilty
    - veth: apply qdisc backpressure on full ring to reduce TX drops
 
  - Ethernet switches:
    - Microchip (kzZ88x3): add ETS scheduler support
 
  - Ethernet PHYs:
    - RealTek (rtl8211):
      - add support for WoL magic packet
      - add support for PHY LEDs
 
  - CAN:
    - Adds RZ/G3E CANFD support to the rcar_canfd driver.
    - Preparatory work for CAN-XL support.
    - Add self-tests framework with support for CAN physical interfaces.
 
  - WiFi:
    - mac80211:
      - scan improvements with multi-link operation (MLO)
    - Qualcomm (ath12k):
      - enable AHB support for IPQ5332
      - add monitor interface support to QCN9274
      - add multi-link operation support to WCN7850
      - add 802.11d scan offload support to WCN7850
      - monitor mode for WCN7850, better 6 GHz regulatory
    - Qualcomm (ath11k):
      - restore hibernation support
    - MediaTek (mt76):
      - WiFi-7 improvements
      - implement support for mt7990
    - Intel (iwlwifi):
      - enhanced multi-link single-radio (EMLSR) support on 5 GHz links
      - rework device configuration
    - RealTek (rtw88):
      - improve throughput for RTL8814AU
    - RealTek (rtw89):
      - add multi-link operation support
      - STA/P2P concurrency improvements
      - support different SAR configs by antenna
 
  - Bluetooth:
    - introduce HCI Driver protocol
    - btintel_pcie: do not generate coredump for diagnostic events
    - btusb: add HCI Drv commands for configuring altsetting
    - btusb: add RTL8851BE device 0x0bda:0xb850
    - btusb: add new VID/PID 13d3/3584 for MT7922
    - btusb: add new VID/PID 13d3/3630 and 13d3/3613 for MT7925
    - btnxpuart: implement host-wakeup feature
 
 Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Paolo Abeni:
 "Core:

   - Implement the Device Memory TCP transmit path, allowing zero-copy
     data transmission on top of TCP from e.g. GPU memory to the wire.

   - Move all the IPv6 routing tables management outside the RTNL scope,
     under its own lock and RCU. The route control path is now 3x times
     faster.

   - Convert queue related netlink ops to instance lock, reducing again
     the scope of the RTNL lock. This improves the control plane
     scalability.

   - Refactor the software crc32c implementation, removing unneeded
     abstraction layers and improving significantly the related
     micro-benchmarks.

   - Optimize the GRO engine for UDP-tunneled traffic, for a 10%
     performance improvement in related stream tests.

   - Cover more per-CPU storage with local nested BH locking; this is a
     prep work to remove the current per-CPU lock in local_bh_disable()
     on PREMPT_RT.

   - Introduce and use nlmsg_payload helper, combining buffer bounds
     verification with accessing payload carried by netlink messages.

  Netfilter:

   - Rewrite the procfs conntrack table implementation, improving
     considerably the dump performance. A lot of user-space tools still
     use this interface.

   - Implement support for wildcard netdevice in netdev basechain and
     flowtables.

   - Integrate conntrack information into nft trace infrastructure.

   - Export set count and backend name to userspace, for better
     introspection.

  BPF:

   - BPF qdisc support: BPF-qdisc can be implemented with BPF struct_ops
     programs and can be controlled in similar way to traditional qdiscs
     using the "tc qdisc" command.

   - Refactor the UDP socket iterator, addressing long standing issues
     WRT duplicate hits or missed sockets.

  Protocols:

   - Improve TCP receive buffer auto-tuning and increase the default
     upper bound for the receive buffer; overall this improves the
     single flow maximum thoughput on 200Gbs link by over 60%.

   - Add AFS GSSAPI security class to AF_RXRPC; it provides transport
     security for connections to the AFS fileserver and VL server.

   - Improve TCP multipath routing, so that the sources address always
     matches the nexthop device.

   - Introduce SO_PASSRIGHTS for AF_UNIX, to allow disabling SCM_RIGHTS,
     and thus preventing DoS caused by passing around problematic FDs.

   - Retire DCCP socket. DCCP only receives updates for bugs, and major
     distros disable it by default. Its removal allows for better
     organisation of TCP fields to reduce the number of cache lines hit
     in the fast path.

   - Extend TCP drop-reason support to cover PAWS checks.

  Driver API:

   - Reorganize PTP ioctl flag support to require an explicit opt-in for
     the drivers, avoiding the problem of drivers not rejecting new
     unsupported flags.

   - Converted several device drivers to timestamping APIs.

   - Introduce per-PHY ethtool dump helpers, improving the support for
     dump operations targeting PHYs.

  Tests and tooling:

   - Add support for classic netlink in user space C codegen, so that
     ynl-c can now read, create and modify links, routes addresses and
     qdisc layer configuration.

   - Add ynl sub-types for binary attributes, allowing ynl-c to output
     known struct instead of raw binary data, clarifying the classic
     netlink output.

   - Extend MPTCP selftests to improve the code-coverage.

   - Add tests for XDP tail adjustment in AF_XDP.

  New hardware / drivers:

   - OpenVPN virtual driver: offload OpenVPN data channels processing to
     the kernel-space, increasing the data transfer throughput WRT the
     user-space implementation.

   - Renesas glue driver for the gigabit ethernet RZ/V2H(P) SoC.

   - Broadcom asp-v3.0 ethernet driver.

   - AMD Renoir ethernet device.

   - ReakTek MT9888 2.5G ethernet PHY driver.

   - Aeonsemi 10G C45 PHYs driver.

  Drivers:

   - Ethernet high-speed NICs:
       - nVidia/Mellanox (mlx5):
           - refactor the steering table handling to significantly
             reduce the amount of memory used
           - add support for complex matches in H/W flow steering
           - improve flow streeing error handling
           - convert to netdev instance locking
       - Intel (100G, ice, igb, ixgbe, idpf):
           - ice: add switchdev support for LLDP traffic over VF
           - ixgbe: add firmware manipulation and regions devlink support
           - igb: introduce support for frame transmission premption
           - igb: adds persistent NAPI configuration
           - idpf: introduce RDMA support
           - idpf: add initial PTP support
       - Meta (fbnic):
           - extend hardware stats coverage
           - add devlink dev flash support
       - Broadcom (bnxt):
           - add support for RX-side device memory TCP
       - Wangxun (txgbe):
           - implement support for udp tunnel offload
           - complete PTP and SRIOV support for AML 25G/10G devices

   - Ethernet NICs embedded and virtual:
       - Google (gve):
           - add device memory TCP TX support
       - Amazon (ena):
           - support persistent per-NAPI config
       - Airoha:
           - add H/W support for L2 traffic offload
           - add per flow stats for flow offloading
       - RealTek (rtl8211): add support for WoL magic packet
       - Synopsys (stmmac):
           - dwmac-socfpga 1000BaseX support
           - add Loongson-2K3000 support
           - introduce support for hardware-accelerated VLAN stripping
       - Broadcom (bcmgenet):
           - expose more H/W stats
       - Freescale (enetc, dpaa2-eth):
           - enetc: add MAC filter, VLAN filter RSS and loopback support
           - dpaa2-eth: convert to H/W timestamping APIs
       - vxlan: convert FDB table to rhashtable, for better scalabilty
       - veth: apply qdisc backpressure on full ring to reduce TX drops

   - Ethernet switches:
       - Microchip (kzZ88x3): add ETS scheduler support

   - Ethernet PHYs:
       - RealTek (rtl8211):
           - add support for WoL magic packet
           - add support for PHY LEDs

   - CAN:
       - Adds RZ/G3E CANFD support to the rcar_canfd driver.
       - Preparatory work for CAN-XL support.
       - Add self-tests framework with support for CAN physical interfaces.

   - WiFi:
       - mac80211:
           - scan improvements with multi-link operation (MLO)
       - Qualcomm (ath12k):
           - enable AHB support for IPQ5332
           - add monitor interface support to QCN9274
           - add multi-link operation support to WCN7850
           - add 802.11d scan offload support to WCN7850
           - monitor mode for WCN7850, better 6 GHz regulatory
       - Qualcomm (ath11k):
           - restore hibernation support
       - MediaTek (mt76):
           - WiFi-7 improvements
           - implement support for mt7990
       - Intel (iwlwifi):
           - enhanced multi-link single-radio (EMLSR) support on 5 GHz links
           - rework device configuration
       - RealTek (rtw88):
           - improve throughput for RTL8814AU
       - RealTek (rtw89):
           - add multi-link operation support
           - STA/P2P concurrency improvements
           - support different SAR configs by antenna

   - Bluetooth:
       - introduce HCI Driver protocol
       - btintel_pcie: do not generate coredump for diagnostic events
       - btusb: add HCI Drv commands for configuring altsetting
       - btusb: add RTL8851BE device 0x0bda:0xb850
       - btusb: add new VID/PID 13d3/3584 for MT7922
       - btusb: add new VID/PID 13d3/3630 and 13d3/3613 for MT7925
       - btnxpuart: implement host-wakeup feature"

* tag 'net-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1611 commits)
  selftests/bpf: Fix bpf selftest build warning
  selftests: netfilter: Fix skip of wildcard interface test
  net: phy: mscc: Stop clearing the the UDPv4 checksum for L2 frames
  net: openvswitch: Fix the dead loop of MPLS parse
  calipso: Don't call calipso functions for AF_INET sk.
  selftests/tc-testing: Add a test for HFSC eltree double add with reentrant enqueue behaviour on netem
  net_sched: hfsc: Address reentrant enqueue adding class to eltree twice
  octeontx2-pf: QOS: Refactor TC_HTB_LEAF_DEL_LAST callback
  octeontx2-pf: QOS: Perform cache sync on send queue teardown
  net: mana: Add support for Multi Vports on Bare metal
  net: devmem: ncdevmem: remove unused variable
  net: devmem: ksft: upgrade rx test to send 1K data
  net: devmem: ksft: add 5 tuple FS support
  net: devmem: ksft: add exit_wait to make rx test pass
  net: devmem: ksft: add ipv4 support
  net: devmem: preserve sockc_err
  page_pool: fix ugly page_pool formatting
  net: devmem: move list_add to net_devmem_bind_dmabuf.
  selftests: netfilter: nft_queue.sh: include file transfer duration in log message
  net: phy: mscc: Fix memory leak when using one step timestamping
  ...
2025-05-28 15:24:36 -07:00
Linus Torvalds
785cdec46e Core x86 updates for v6.16:
Boot code changes:
 
  - A large series of changes to reorganize the x86 boot code into a better isolated
    and easier to maintain base of PIC early startup code in arch/x86/boot/startup/,
    by Ard Biesheuvel.
 
    Motivation & background:
 
 	| Since commit
 	|
 	|    c88d71508e ("x86/boot/64: Rewrite startup_64() in C")
 	|
 	| dated Jun 6 2017, we have been using C code on the boot path in a way
 	| that is not supported by the toolchain, i.e., to execute non-PIC C
 	| code from a mapping of memory that is different from the one provided
 	| to the linker. It should have been obvious at the time that this was a
 	| bad idea, given the need to sprinkle fixup_pointer() calls left and
 	| right to manipulate global variables (including non-pointer variables)
 	| without crashing.
 	|
 	| This C startup code has been expanding, and in particular, the SEV-SNP
 	| startup code has been expanding over the past couple of years, and
 	| grown many of these warts, where the C code needs to use special
 	| annotations or helpers to access global objects.
 
    This tree includes the first phase of this work-in-progress x86 boot code
    reorganization.
 
 Scalability enhancements and micro-optimizations:
 
  - Improve code-patching scalability (Eric Dumazet)
  - Remove MFENCEs for X86_BUG_CLFLUSH_MONITOR (Andrew Cooper)
 
 CPU features enumeration updates:
 
  - Thorough reorganization and cleanup of CPUID parsing APIs (Ahmed S. Darwish)
  - Fix, refactor and clean up the cacheinfo code (Ahmed S. Darwish, Thomas Gleixner)
  - Update CPUID bitfields to x86-cpuid-db v2.3 (Ahmed S. Darwish)
 
 Memory management changes:
 
  - Allow temporary MMs when IRQs are on (Andy Lutomirski)
  - Opt-in to IRQs-off activate_mm() (Andy Lutomirski)
  - Simplify choose_new_asid() and generate better code (Borislav Petkov)
  - Simplify 32-bit PAE page table handling (Dave Hansen)
  - Always use dynamic memory layout (Kirill A. Shutemov)
  - Make SPARSEMEM_VMEMMAP the only memory model (Kirill A. Shutemov)
  - Make 5-level paging support unconditional (Kirill A. Shutemov)
  - Stop prefetching current->mm->mmap_lock on page faults (Mateusz Guzik)
  - Predict valid_user_address() returning true (Mateusz Guzik)
  - Consolidate initmem_init() (Mike Rapoport)
 
 FPU support and vector computing:
 
  - Enable Intel APX support (Chang S. Bae)
  - Reorgnize and clean up the xstate code (Chang S. Bae)
  - Make task_struct::thread constant size (Ingo Molnar)
  - Restore fpu_thread_struct_whitelist() to fix CONFIG_HARDENED_USERCOPY=y
    (Kees Cook)
  - Simplify the switch_fpu_prepare() + switch_fpu_finish() logic (Oleg Nesterov)
  - Always preserve non-user xfeatures/flags in __state_perm (Sean Christopherson)
 
 Microcode loader changes:
 
  - Help users notice when running old Intel microcode (Dave Hansen)
  - AMD: Do not return error when microcode update is not necessary (Annie Li)
  - AMD: Clean the cache if update did not load microcode (Boris Ostrovsky)
 
 Code patching (alternatives) changes:
 
  - Simplify, reorganize and clean up the x86 text-patching code (Ingo Molnar)
  - Make smp_text_poke_batch_process() subsume smp_text_poke_batch_finish()
    (Nikolay Borisov)
  - Refactor the {,un}use_temporary_mm() code (Peter Zijlstra)
 
 Debugging support:
 
  - Add early IDT and GDT loading to debug relocate_kernel() bugs (David Woodhouse)
  - Print the reason for the last reset on modern AMD CPUs (Yazen Ghannam)
  - Add AMD Zen debugging document (Mario Limonciello)
  - Fix opcode map (!REX2) superscript tags (Masami Hiramatsu)
  - Stop decoding i64 instructions in x86-64 mode at opcode (Masami Hiramatsu)
 
 CPU bugs and bug mitigations:
 
  - Remove X86_BUG_MMIO_UNKNOWN (Borislav Petkov)
  - Fix SRSO reporting on Zen1/2 with SMT disabled (Borislav Petkov)
  - Restructure and harmonize the various CPU bug mitigation methods
    (David Kaplan)
  - Fix spectre_v2 mitigation default on Intel (Pawan Gupta)
 
 MSR API:
 
  - Large MSR code and API cleanup (Xin Li)
  - In-kernel MSR API type cleanups and renames (Ingo Molnar)
 
 PKEYS:
 
  - Simplify PKRU update in signal frame (Chang S. Bae)
 
 NMI handling code:
 
  - Clean up, refactor and simplify the NMI handling code (Sohil Mehta)
  - Improve NMI duration console printouts (Sohil Mehta)
 
 Paravirt guests interface:
 
  - Restrict PARAVIRT_XXL to 64-bit only (Kirill A. Shutemov)
 
 SEV support:
 
  - Share the sev_secrets_pa value again (Tom Lendacky)
 
 x86 platform changes:
 
  - Introduce the <asm/amd/> header namespace (Ingo Molnar)
  - i2c: piix4, x86/platform: Move the SB800 PIIX4 FCH definitions to <asm/amd/fch.h>
    (Mario Limonciello)
 
 Fixes and cleanups:
 
  - x86 assembly code cleanups and fixes (Uros Bizjak)
 
  - Misc fixes and cleanups (Andi Kleen, Andy Lutomirski, Andy Shevchenko,
    Ard Biesheuvel, Bagas Sanjaya, Baoquan He, Borislav Petkov, Chang S. Bae,
    Chao Gao, Dan Williams, Dave Hansen, David Kaplan, David Woodhouse,
    Eric Biggers, Ingo Molnar, Josh Poimboeuf, Juergen Gross, Malaya Kumar Rout,
    Mario Limonciello, Nathan Chancellor, Oleg Nesterov, Pawan Gupta,
    Peter Zijlstra, Shivank Garg, Sohil Mehta, Thomas Gleixner, Uros Bizjak,
    Xin Li)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-core-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core x86 updates from Ingo Molnar:
 "Boot code changes:

   - A large series of changes to reorganize the x86 boot code into a
     better isolated and easier to maintain base of PIC early startup
     code in arch/x86/boot/startup/, by Ard Biesheuvel.

     Motivation & background:

  	| Since commit
  	|
  	|    c88d71508e ("x86/boot/64: Rewrite startup_64() in C")
  	|
  	| dated Jun 6 2017, we have been using C code on the boot path in a way
  	| that is not supported by the toolchain, i.e., to execute non-PIC C
  	| code from a mapping of memory that is different from the one provided
  	| to the linker. It should have been obvious at the time that this was a
  	| bad idea, given the need to sprinkle fixup_pointer() calls left and
  	| right to manipulate global variables (including non-pointer variables)
  	| without crashing.
  	|
  	| This C startup code has been expanding, and in particular, the SEV-SNP
  	| startup code has been expanding over the past couple of years, and
  	| grown many of these warts, where the C code needs to use special
  	| annotations or helpers to access global objects.

     This tree includes the first phase of this work-in-progress x86
     boot code reorganization.

  Scalability enhancements and micro-optimizations:

   - Improve code-patching scalability (Eric Dumazet)

   - Remove MFENCEs for X86_BUG_CLFLUSH_MONITOR (Andrew Cooper)

  CPU features enumeration updates:

   - Thorough reorganization and cleanup of CPUID parsing APIs (Ahmed S.
     Darwish)

   - Fix, refactor and clean up the cacheinfo code (Ahmed S. Darwish,
     Thomas Gleixner)

   - Update CPUID bitfields to x86-cpuid-db v2.3 (Ahmed S. Darwish)

  Memory management changes:

   - Allow temporary MMs when IRQs are on (Andy Lutomirski)

   - Opt-in to IRQs-off activate_mm() (Andy Lutomirski)

   - Simplify choose_new_asid() and generate better code (Borislav
     Petkov)

   - Simplify 32-bit PAE page table handling (Dave Hansen)

   - Always use dynamic memory layout (Kirill A. Shutemov)

   - Make SPARSEMEM_VMEMMAP the only memory model (Kirill A. Shutemov)

   - Make 5-level paging support unconditional (Kirill A. Shutemov)

   - Stop prefetching current->mm->mmap_lock on page faults (Mateusz
     Guzik)

   - Predict valid_user_address() returning true (Mateusz Guzik)

   - Consolidate initmem_init() (Mike Rapoport)

  FPU support and vector computing:

   - Enable Intel APX support (Chang S. Bae)

   - Reorgnize and clean up the xstate code (Chang S. Bae)

   - Make task_struct::thread constant size (Ingo Molnar)

   - Restore fpu_thread_struct_whitelist() to fix
     CONFIG_HARDENED_USERCOPY=y (Kees Cook)

   - Simplify the switch_fpu_prepare() + switch_fpu_finish() logic (Oleg
     Nesterov)

   - Always preserve non-user xfeatures/flags in __state_perm (Sean
     Christopherson)

  Microcode loader changes:

   - Help users notice when running old Intel microcode (Dave Hansen)

   - AMD: Do not return error when microcode update is not necessary
     (Annie Li)

   - AMD: Clean the cache if update did not load microcode (Boris
     Ostrovsky)

  Code patching (alternatives) changes:

   - Simplify, reorganize and clean up the x86 text-patching code (Ingo
     Molnar)

   - Make smp_text_poke_batch_process() subsume
     smp_text_poke_batch_finish() (Nikolay Borisov)

   - Refactor the {,un}use_temporary_mm() code (Peter Zijlstra)

  Debugging support:

   - Add early IDT and GDT loading to debug relocate_kernel() bugs
     (David Woodhouse)

   - Print the reason for the last reset on modern AMD CPUs (Yazen
     Ghannam)

   - Add AMD Zen debugging document (Mario Limonciello)

   - Fix opcode map (!REX2) superscript tags (Masami Hiramatsu)

   - Stop decoding i64 instructions in x86-64 mode at opcode (Masami
     Hiramatsu)

  CPU bugs and bug mitigations:

   - Remove X86_BUG_MMIO_UNKNOWN (Borislav Petkov)

   - Fix SRSO reporting on Zen1/2 with SMT disabled (Borislav Petkov)

   - Restructure and harmonize the various CPU bug mitigation methods
     (David Kaplan)

   - Fix spectre_v2 mitigation default on Intel (Pawan Gupta)

  MSR API:

   - Large MSR code and API cleanup (Xin Li)

   - In-kernel MSR API type cleanups and renames (Ingo Molnar)

  PKEYS:

   - Simplify PKRU update in signal frame (Chang S. Bae)

  NMI handling code:

   - Clean up, refactor and simplify the NMI handling code (Sohil Mehta)

   - Improve NMI duration console printouts (Sohil Mehta)

  Paravirt guests interface:

   - Restrict PARAVIRT_XXL to 64-bit only (Kirill A. Shutemov)

  SEV support:

   - Share the sev_secrets_pa value again (Tom Lendacky)

  x86 platform changes:

   - Introduce the <asm/amd/> header namespace (Ingo Molnar)

   - i2c: piix4, x86/platform: Move the SB800 PIIX4 FCH definitions to
     <asm/amd/fch.h> (Mario Limonciello)

  Fixes and cleanups:

   - x86 assembly code cleanups and fixes (Uros Bizjak)

   - Misc fixes and cleanups (Andi Kleen, Andy Lutomirski, Andy
     Shevchenko, Ard Biesheuvel, Bagas Sanjaya, Baoquan He, Borislav
     Petkov, Chang S. Bae, Chao Gao, Dan Williams, Dave Hansen, David
     Kaplan, David Woodhouse, Eric Biggers, Ingo Molnar, Josh Poimboeuf,
     Juergen Gross, Malaya Kumar Rout, Mario Limonciello, Nathan
     Chancellor, Oleg Nesterov, Pawan Gupta, Peter Zijlstra, Shivank
     Garg, Sohil Mehta, Thomas Gleixner, Uros Bizjak, Xin Li)"

* tag 'x86-core-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (331 commits)
  x86/bugs: Fix spectre_v2 mitigation default on Intel
  x86/bugs: Restructure ITS mitigation
  x86/xen/msr: Fix uninitialized variable 'err'
  x86/msr: Remove a superfluous inclusion of <asm/asm.h>
  x86/paravirt: Restrict PARAVIRT_XXL to 64-bit only
  x86/mm/64: Make 5-level paging support unconditional
  x86/mm/64: Make SPARSEMEM_VMEMMAP the only memory model
  x86/mm/64: Always use dynamic memory layout
  x86/bugs: Fix indentation due to ITS merge
  x86/cpuid: Rename hypervisor_cpuid_base()/for_each_possible_hypervisor_cpuid_base() to cpuid_base_hypervisor()/for_each_possible_cpuid_base_hypervisor()
  x86/cpu/intel: Rename CPUID(0x2) descriptors iterator parameter
  x86/cacheinfo: Rename CPUID(0x2) descriptors iterator parameter
  x86/cpuid: Rename cpuid_get_leaf_0x2_regs() to cpuid_leaf_0x2()
  x86/cpuid: Rename have_cpuid_p() to cpuid_feature()
  x86/cpuid: Set <asm/cpuid/api.h> as the main CPUID header
  x86/cpuid: Move CPUID(0x2) APIs into <cpuid/api.h>
  x86/msr: Add rdmsrl_on_cpu() compatibility wrapper
  x86/mm: Fix kernel-doc descriptions of various pgtable methods
  x86/asm-offsets: Export certain 'struct cpuinfo_x86' fields for 64-bit asm use too
  x86/boot: Defer initialization of VM space related global variables
  ...
2025-05-26 16:04:17 -07:00
Sebastian Andrzej Siewior
a1f1acb9c5 netfilter: nf_dup{4, 6}: Move duplication check to task_struct
nf_skb_duplicated is a per-CPU variable and relies on disabled BH for its
locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
this data structure requires explicit locking.

Due to the recursion involved, the simplest change is to make it a
per-task variable.

Move the per-CPU variable nf_skb_duplicated to task_struct and name it
in_nf_duplicate. Add it to the existing bitfield so it doesn't use
additional memory.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-05-23 13:57:12 +02:00
Peter Zijlstra
676e8cf70c sched,livepatch: Untangle cond_resched() and live-patching
With the goal of deprecating / removing VOLUNTARY preempt, live-patch
needs to stop relying on cond_resched() to make forward progress.

Instead, rely on schedule() with TASK_FREEZABLE set. Just like
live-patching, the freezer needs to be able to stop tasks in a safe /
known state.

[bigeasy: use likely() in __klp_sched_try_switch() and update comments]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Tested-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20250509113659.wkP_HJ5z@linutronix.de
2025-05-14 13:16:24 +02:00
Lance Yang
e711faaafb hung_task: replace blocker_mutex with encoded blocker
Patch series "hung_task: extend blocking task stacktrace dump to
semaphore", v5.

Inspired by mutex blocker tracking[1], this patch series extend the
feature to not only dump the blocker task holding a mutex but also to
support semaphores.  Unlike mutexes, semaphores lack explicit ownership
tracking, making it challenging to identify the root cause of hangs.  To
address this, we introduce a last_holder field to the semaphore structure,
which is updated when a task successfully calls down() and cleared during
up().

The assumption is that if a task is blocked on a semaphore, the holders
must not have released it.  While this does not guarantee that the last
holder is one of the current blockers, it likely provides a practical hint
for diagnosing semaphore-related stalls.

With this change, the hung task detector can now show blocker task's info
like below:

[Tue Apr  8 12:19:07 2025] INFO: task cat:945 blocked for more than 120 seconds.
[Tue Apr  8 12:19:07 2025]       Tainted: G            E      6.14.0-rc6+ #1
[Tue Apr  8 12:19:07 2025] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[Tue Apr  8 12:19:07 2025] task:cat             state:D stack:0     pid:945   tgid:945   ppid:828    task_flags:0x400000 flags:0x00000000
[Tue Apr  8 12:19:07 2025] Call Trace:
[Tue Apr  8 12:19:07 2025]  <TASK>
[Tue Apr  8 12:19:07 2025]  __schedule+0x491/0xbd0
[Tue Apr  8 12:19:07 2025]  schedule+0x27/0xf0
[Tue Apr  8 12:19:07 2025]  schedule_timeout+0xe3/0xf0
[Tue Apr  8 12:19:07 2025]  ? __folio_mod_stat+0x2a/0x80
[Tue Apr  8 12:19:07 2025]  ? set_ptes.constprop.0+0x27/0x90
[Tue Apr  8 12:19:07 2025]  __down_common+0x155/0x280
[Tue Apr  8 12:19:07 2025]  down+0x53/0x70
[Tue Apr  8 12:19:07 2025]  read_dummy_semaphore+0x23/0x60
[Tue Apr  8 12:19:07 2025]  full_proxy_read+0x5f/0xa0
[Tue Apr  8 12:19:07 2025]  vfs_read+0xbc/0x350
[Tue Apr  8 12:19:07 2025]  ? __count_memcg_events+0xa5/0x140
[Tue Apr  8 12:19:07 2025]  ? count_memcg_events.constprop.0+0x1a/0x30
[Tue Apr  8 12:19:07 2025]  ? handle_mm_fault+0x180/0x260
[Tue Apr  8 12:19:07 2025]  ksys_read+0x66/0xe0
[Tue Apr  8 12:19:07 2025]  do_syscall_64+0x51/0x120
[Tue Apr  8 12:19:07 2025]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[Tue Apr  8 12:19:07 2025] RIP: 0033:0x7f419478f46e
[Tue Apr  8 12:19:07 2025] RSP: 002b:00007fff1c4d2668 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[Tue Apr  8 12:19:07 2025] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f419478f46e
[Tue Apr  8 12:19:07 2025] RDX: 0000000000020000 RSI: 00007f4194683000 RDI: 0000000000000003
[Tue Apr  8 12:19:07 2025] RBP: 00007f4194683000 R08: 00007f4194682010 R09: 0000000000000000
[Tue Apr  8 12:19:07 2025] R10: fffffffffffffbc5 R11: 0000000000000246 R12: 0000000000000000
[Tue Apr  8 12:19:07 2025] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000
[Tue Apr  8 12:19:07 2025]  </TASK>
[Tue Apr  8 12:19:07 2025] INFO: task cat:945 blocked on a semaphore likely last held by task cat:938
[Tue Apr  8 12:19:07 2025] task:cat             state:S stack:0     pid:938   tgid:938   ppid:584    task_flags:0x400000 flags:0x00000000
[Tue Apr  8 12:19:07 2025] Call Trace:
[Tue Apr  8 12:19:07 2025]  <TASK>
[Tue Apr  8 12:19:07 2025]  __schedule+0x491/0xbd0
[Tue Apr  8 12:19:07 2025]  ? _raw_spin_unlock_irqrestore+0xe/0x40
[Tue Apr  8 12:19:07 2025]  schedule+0x27/0xf0
[Tue Apr  8 12:19:07 2025]  schedule_timeout+0x77/0xf0
[Tue Apr  8 12:19:07 2025]  ? __pfx_process_timeout+0x10/0x10
[Tue Apr  8 12:19:07 2025]  msleep_interruptible+0x49/0x60
[Tue Apr  8 12:19:07 2025]  read_dummy_semaphore+0x2d/0x60
[Tue Apr  8 12:19:07 2025]  full_proxy_read+0x5f/0xa0
[Tue Apr  8 12:19:07 2025]  vfs_read+0xbc/0x350
[Tue Apr  8 12:19:07 2025]  ? __count_memcg_events+0xa5/0x140
[Tue Apr  8 12:19:07 2025]  ? count_memcg_events.constprop.0+0x1a/0x30
[Tue Apr  8 12:19:07 2025]  ? handle_mm_fault+0x180/0x260
[Tue Apr  8 12:19:07 2025]  ksys_read+0x66/0xe0
[Tue Apr  8 12:19:07 2025]  do_syscall_64+0x51/0x120
[Tue Apr  8 12:19:07 2025]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[Tue Apr  8 12:19:07 2025] RIP: 0033:0x7f7c584a646e
[Tue Apr  8 12:19:07 2025] RSP: 002b:00007ffdba8ce158 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[Tue Apr  8 12:19:07 2025] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f7c584a646e
[Tue Apr  8 12:19:07 2025] RDX: 0000000000020000 RSI: 00007f7c5839a000 RDI: 0000000000000003
[Tue Apr  8 12:19:07 2025] RBP: 00007f7c5839a000 R08: 00007f7c58399010 R09: 0000000000000000
[Tue Apr  8 12:19:07 2025] R10: fffffffffffffbc5 R11: 0000000000000246 R12: 0000000000000000
[Tue Apr  8 12:19:07 2025] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000
[Tue Apr  8 12:19:07 2025]  </TASK>


This patch (of 3):

This patch replaces 'struct mutex *blocker_mutex' with 'unsigned long
blocker', as only one blocker is active at a time.

The blocker filed can store both the lock addrees and the lock type, with
LSB used to encode the type as Masami suggested, making it easier to
extend the feature to cover other types of locks.

Also, once the lock type is determined, we can directly extract the
address and cast it to a lock pointer ;)

Link: https://lkml.kernel.org/r/20250414145945.84916-1-ioworker0@gmail.com
Link: https://lore.kernel.org/all/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com [1]
Link: https://lkml.kernel.org/r/20250414145945.84916-2-ioworker0@gmail.com
Signed-off-by: Mingzhe Yang <mingzhe.yang@ly.com>
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Stultz <jstultz@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yongliang Gao <leonylgao@tencent.com>
Cc: Zi Li <amaindex@outlook.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-11 17:54:07 -07:00
Ingo Molnar
cb7ca40a38 x86/fpu: Make task_struct::thread constant size
Turn thread.fpu into a pointer. Since most FPU code internals work by passing
around the FPU pointer already, the code generation impact is small.

This allows us to remove the old kludge of task_struct being variable size:

  struct task_struct {

       ...
       /*
        * New fields for task_struct should be added above here, so that
        * they are included in the randomized portion of task_struct.
        */
       randomized_struct_fields_end

       /* CPU-specific state of this task: */
       struct thread_struct            thread;

       /*
        * WARNING: on x86, 'thread_struct' contains a variable-sized
        * structure.  It *MUST* be at the end of 'task_struct'.
        *
        * Do not put anything below here!
        */
  };

... which creates a number of problems, such as requiring thread_struct to be
the last member of the struct - not allowing it to be struct-randomized, etc.

But the primary motivation is to allow the decoupling of task_struct from
hardware details (<asm/processor.h> in particular), and to eventually allow
the per-task infrastructure:

   DECLARE_PER_TASK(type, name);
   ...
   per_task(current, name) = val;

... which requires task_struct to be a constant size struct.

The fpu_thread_struct_whitelist() quirk to hardened usercopy can be removed,
now that the FPU structure is not embedded in the task struct anymore, which
reduces text footprint a bit.

Fixed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chang S. Bae <chang.seok.bae@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250409211127.3544993-4-mingo@kernel.org
2025-04-14 08:18:29 +02:00
Linus Torvalds
d6b02199cd - The 7 patch series "powerpc/crash: use generic crashkernel
reservation" from Sourabh Jain changes powerpc's kexec code to use more
   of the generic layers.
 
 - The 2 patch series "get_maintainer: report subsystem status
   separately" from Vlastimil Babka makes some long-requested improvements
   to the get_maintainer output.
 
 - The 4 patch series "ucount: Simplify refcounting with rcuref_t" from
   Sebastian Siewior cleans up and optimizing the refcounting in the ucount
   code.
 
 - The 12 patch series "reboot: support runtime configuration of
   emergency hw_protection action" from Ahmad Fatoum improves the ability
   for a driver to perform an emergency system shutdown or reboot.
 
 - The 16 patch series "Converge on using secs_to_jiffies() part two"
   from Easwar Hariharan performs further migrations from
   msecs_to_jiffies() to secs_to_jiffies().
 
 - The 7 patch series "lib/interval_tree: add some test cases and
   cleanup" from Wei Yang permits more userspace testing of kernel library
   code, adds some more tests and performs some cleanups.
 
 - The 2 patch series "hung_task: Dump the blocking task stacktrace" from
   Masami Hiramatsu arranges for the hung_task detector to dump the stack
   of the blocking task and not just that of the blocked task.
 
 - The 4 patch series "resource: Split and use DEFINE_RES*() macros" from
   Andy Shevchenko provides some cleanups to the resource definition
   macros.
 
 - Plus the usual shower of singleton patches - please see the individual
   changelogs for details.
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Merge tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - The series "powerpc/crash: use generic crashkernel reservation" from
   Sourabh Jain changes powerpc's kexec code to use more of the generic
   layers.

 - The series "get_maintainer: report subsystem status separately" from
   Vlastimil Babka makes some long-requested improvements to the
   get_maintainer output.

 - The series "ucount: Simplify refcounting with rcuref_t" from
   Sebastian Siewior cleans up and optimizing the refcounting in the
   ucount code.

 - The series "reboot: support runtime configuration of emergency
   hw_protection action" from Ahmad Fatoum improves the ability for a
   driver to perform an emergency system shutdown or reboot.

 - The series "Converge on using secs_to_jiffies() part two" from Easwar
   Hariharan performs further migrations from msecs_to_jiffies() to
   secs_to_jiffies().

 - The series "lib/interval_tree: add some test cases and cleanup" from
   Wei Yang permits more userspace testing of kernel library code, adds
   some more tests and performs some cleanups.

 - The series "hung_task: Dump the blocking task stacktrace" from Masami
   Hiramatsu arranges for the hung_task detector to dump the stack of
   the blocking task and not just that of the blocked task.

 - The series "resource: Split and use DEFINE_RES*() macros" from Andy
   Shevchenko provides some cleanups to the resource definition macros.

 - Plus the usual shower of singleton patches - please see the
   individual changelogs for details.

* tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits)
  mailmap: consolidate email addresses of Alexander Sverdlin
  fs/procfs: fix the comment above proc_pid_wchan()
  relay: use kasprintf() instead of fixed buffer formatting
  resource: replace open coded variant of DEFINE_RES()
  resource: replace open coded variants of DEFINE_RES_*_NAMED()
  resource: replace open coded variant of DEFINE_RES_NAMED_DESC()
  resource: split DEFINE_RES_NAMED_DESC() out of DEFINE_RES_NAMED()
  samples: add hung_task detector mutex blocking sample
  hung_task: show the blocker task if the task is hung on mutex
  kexec_core: accept unaccepted kexec segments' destination addresses
  watchdog/perf: optimize bytes copied and remove manual NUL-termination
  lib/interval_tree: fix the comment of interval_tree_span_iter_next_gap()
  lib/interval_tree: skip the check before go to the right subtree
  lib/interval_tree: add test case for span iteration
  lib/interval_tree: add test case for interval_tree_iter_xxx() helpers
  lib/rbtree: add random seed
  lib/rbtree: split tests
  lib/rbtree: enable userland test suite for rbtree related data structure
  checkpatch: describe --min-conf-desc-length
  scripts/gdb/symbols: determine KASLR offset on s390
  ...
2025-04-01 10:06:52 -07:00
Linus Torvalds
88221ac0d5 Latency tracing changes for v6.15:
- Add some trace events to osnoise and timerlat sample generation
 
   This adds more information to the osnoise and timerlat tracers as well as
   allows BPF programs to be attached to these locations to extract even more
   data.
 
 - Fix to DECLARE_TRACE_CONDITION() macro
 
   It wasn't used but now will be and it happened to be broken causing the
   build to fail.
 
 - Add scheduler specification monitors to runtime verifier (RV)
 
   This is a continuation of Daniel Bristot's work.
 
   RV allows monitors to run and react concurrently. Running the cumulative
   model is equivalent to running single components using the same
   reactors, with the advantage that it's easier to point out which
   specification failed in case of error.
 
   This update introduces nested monitors to RV, in short, the sysfs
   monitor folder will contain a monitor named sched, which is nothing but
   an empty container for other monitors. Controlling the sched monitor
   (enable, disable, set reactors) controls all nested monitors.
 
   The following scheduling monitors are added:
 
   * sco: scheduling context operations
       Monitor to ensure sched_set_state happens only in thread context
   * tss: task switch while scheduling
       Monitor to ensure sched_switch happens only in scheduling context
   * snroc: set non runnable on its own context
       Monitor to ensure set_state happens only in the respective task's context
   * scpd: schedule called with preemption disabled
       Monitor to ensure schedule is called with preemption disabled
   * snep: schedule does not enable preempt
       Monitor to ensure schedule does not enable preempt
   * sncid: schedule not called with interrupt disabled
       Monitor to ensure schedule is not called with interrupt disabled
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Merge tag 'trace-latency-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull latency tracing updates from Steven Rostedt:

 - Add some trace events to osnoise and timerlat sample generation

   This adds more information to the osnoise and timerlat tracers as
   well as allows BPF programs to be attached to these locations to
   extract even more data.

 - Fix to DECLARE_TRACE_CONDITION() macro

   It wasn't used but now will be and it happened to be broken causing
   the build to fail.

 - Add scheduler specification monitors to runtime verifier (RV)

   This is a continuation of Daniel Bristot's work.

   RV allows monitors to run and react concurrently. Running the
   cumulative model is equivalent to running single components using the
   same reactors, with the advantage that it's easier to point out which
   specification failed in case of error.

   This update introduces nested monitors to RV, in short, the sysfs
   monitor folder will contain a monitor named sched, which is nothing
   but an empty container for other monitors. Controlling the sched
   monitor (enable, disable, set reactors) controls all nested monitors.

   The following scheduling monitors are added:

     - sco: scheduling context operations
       Monitor to ensure sched_set_state happens only in thread context

     - tss: task switch while scheduling
       Monitor to ensure sched_switch happens only in scheduling context

     - snroc: set non runnable on its own context
       Monitor to ensure set_state happens only in the respective task's context

     - scpd: schedule called with preemption disabled
       Monitor to ensure schedule is called with preemption disabled

     - snep: schedule does not enable preempt
       Monitor to ensure schedule does not enable preempt

     - sncid: schedule not called with interrupt disabled
       Monitor to ensure schedule is not called with interrupt disabled

* tag 'trace-latency-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tools/rv: Allow rv list to filter for container
  Documentation/rv: Add docs for the sched monitors
  verification/dot2k: Add support for nested monitors
  tools/rv: Add support for nested monitors
  rv: Add scpd, snep and sncid per-cpu monitors
  rv: Add snroc per-task monitor
  rv: Add sco and tss per-cpu monitors
  rv: Add option for nested monitors and include sched
  sched: Add sched tracepoints for RV task model
  rv: Add license identifiers to monitor files
  tracing: Fix DECLARE_TRACE_CONDITION
  trace/osnoise: Add trace events for samples
2025-03-27 16:03:52 -07:00
Linus Torvalds
327ecdbc0f Performance events updates for v6.15:
Core:
 
   - Move perf_event sysctls into kernel/events/ (Joel Granados)
   - Use POLLHUP for pinned events in error (Namhyung Kim)
   - Avoid the read if the count is already updated (Peter Zijlstra)
   - Allow the EPOLLRDNORM flag for poll (Tao Chen)
 
   - locking/percpu-rwsem: Add guard support (Peter Zijlstra)
     [ NOTE: this got (mis-)merged into the perf tree due to related work. ]
 
 perf_pmu_unregister() related improvements: (Peter Zijlstra)
 
   - Simplify the perf_event_alloc() error path
   - Simplify the perf_pmu_register() error path
   - Simplify perf_pmu_register()
   - Simplify perf_init_event()
   - Simplify perf_event_alloc()
   - Merge struct pmu::pmu_disable_count into struct perf_cpu_pmu_context::pmu_disable_count
   - Add this_cpc() helper
   - Introduce perf_free_addr_filters()
   - Robustify perf_event_free_bpf_prog()
   - Simplify the perf_mmap() control flow
   - Further simplify perf_mmap()
   - Remove retry loop from perf_mmap()
   - Lift event->mmap_mutex in perf_mmap()
   - Detach 'struct perf_cpu_pmu_context' and 'struct pmu' lifetimes
   - Fix perf_mmap() failure path
 
 Uprobes:
 
   - Harden x86 uretprobe syscall trampoline check (Jiri Olsa)
   - Remove redundant spinlock in uprobe_deny_signal() (Liao Chang)
   - Remove the spinlock within handle_singlestep() (Liao Chang)
 
 x86 Intel PMU enhancements:
 
   - Support PEBS counters snapshotting (Kan Liang)
   - Fix intel_pmu_read_event() (Kan Liang)
   - Extend per event callchain limit to branch stack (Kan Liang)
   - Fix system-wide LBR profiling (Kan Liang)
   - Allocate bts_ctx only if necessary (Li RongQing)
   - Apply static call for drain_pebs (Peter Zijlstra)
 
 x86 AMD PMU enhancements: (Ravi Bangoria)
 
   - Remove pointless sample period check
   - Fix ->config to sample period calculation for OP PMU
   - Fix perf_ibs_op.cnt_mask for CurCnt
   - Don't allow freq mode event creation through ->config interface
   - Add PMU specific minimum period
   - Add ->check_period() callback
   - Ceil sample_period to min_period
   - Add support for OP Load Latency Filtering
   - Update DTLB/PageSize decode logic
 
 Hardware breakpoints:
 
   - Return EOPNOTSUPP for unsupported breakpoint type (Saket Kumar Bhaskar)
 
 Hardlockup detector improvements: (Li Huafei)
 
   - perf_event memory leak
   - Warn if watchdog_ev is leaked
 
 Fixes and cleanups:
 
   - Misc fixes and cleanups (Andy Shevchenko, Kan Liang, Peter Zijlstra,
     Ravi Bangoria, Thorsten Blum, XieLudan)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull performance events updates from Ingo Molnar:
 "Core:
   - Move perf_event sysctls into kernel/events/ (Joel Granados)
   - Use POLLHUP for pinned events in error (Namhyung Kim)
   - Avoid the read if the count is already updated (Peter Zijlstra)
   - Allow the EPOLLRDNORM flag for poll (Tao Chen)
   - locking/percpu-rwsem: Add guard support [ NOTE: this got
     (mis-)merged into the perf tree due to related work ] (Peter
     Zijlstra)

  perf_pmu_unregister() related improvements: (Peter Zijlstra)
   - Simplify the perf_event_alloc() error path
   - Simplify the perf_pmu_register() error path
   - Simplify perf_pmu_register()
   - Simplify perf_init_event()
   - Simplify perf_event_alloc()
   - Merge struct pmu::pmu_disable_count into struct
     perf_cpu_pmu_context::pmu_disable_count
   - Add this_cpc() helper
   - Introduce perf_free_addr_filters()
   - Robustify perf_event_free_bpf_prog()
   - Simplify the perf_mmap() control flow
   - Further simplify perf_mmap()
   - Remove retry loop from perf_mmap()
   - Lift event->mmap_mutex in perf_mmap()
   - Detach 'struct perf_cpu_pmu_context' and 'struct pmu' lifetimes
   - Fix perf_mmap() failure path

  Uprobes:
   - Harden x86 uretprobe syscall trampoline check (Jiri Olsa)
   - Remove redundant spinlock in uprobe_deny_signal() (Liao Chang)
   - Remove the spinlock within handle_singlestep() (Liao Chang)

  x86 Intel PMU enhancements:
   - Support PEBS counters snapshotting (Kan Liang)
   - Fix intel_pmu_read_event() (Kan Liang)
   - Extend per event callchain limit to branch stack (Kan Liang)
   - Fix system-wide LBR profiling (Kan Liang)
   - Allocate bts_ctx only if necessary (Li RongQing)
   - Apply static call for drain_pebs (Peter Zijlstra)

  x86 AMD PMU enhancements: (Ravi Bangoria)
   - Remove pointless sample period check
   - Fix ->config to sample period calculation for OP PMU
   - Fix perf_ibs_op.cnt_mask for CurCnt
   - Don't allow freq mode event creation through ->config interface
   - Add PMU specific minimum period
   - Add ->check_period() callback
   - Ceil sample_period to min_period
   - Add support for OP Load Latency Filtering
   - Update DTLB/PageSize decode logic

  Hardware breakpoints:
   - Return EOPNOTSUPP for unsupported breakpoint type (Saket Kumar
     Bhaskar)

  Hardlockup detector improvements: (Li Huafei)
   - perf_event memory leak
   - Warn if watchdog_ev is leaked

  Fixes and cleanups:
   - Misc fixes and cleanups (Andy Shevchenko, Kan Liang, Peter
     Zijlstra, Ravi Bangoria, Thorsten Blum, XieLudan)"

* tag 'perf-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits)
  perf: Fix __percpu annotation
  perf: Clean up pmu specific data
  perf/x86: Remove swap_task_ctx()
  perf/x86/lbr: Fix shorter LBRs call stacks for the system-wide mode
  perf: Supply task information to sched_task()
  perf: attach/detach PMU specific data
  locking/percpu-rwsem: Add guard support
  perf: Save PMU specific data in task_struct
  perf: Extend per event callchain limit to branch stack
  perf/ring_buffer: Allow the EPOLLRDNORM flag for poll
  perf/core: Use POLLHUP for pinned events in error
  perf/core: Use sysfs_emit() instead of scnprintf()
  perf/core: Remove optional 'size' arguments from strscpy() calls
  perf/x86/intel/bts: Check if bts_ctx is allocated when calling BTS functions
  uprobes/x86: Harden uretprobe syscall trampoline check
  watchdog/hardlockup/perf: Warn if watchdog_ev is leaked
  watchdog/hardlockup/perf: Fix perf_event memory leak
  perf/x86: Annotate struct bts_buffer::buf with __counted_by()
  perf/core: Clean up perf_try_init_event()
  perf/core: Fix perf_mmap() failure path
  ...
2025-03-24 21:46:36 -07:00
Linus Torvalds
32b22538be Scheduler updates for v6.15:
[ Merge note, these two commits are identical:
 
    - f3fa0e40df ("sched/clock: Don't define sched_clock_irqtime as static key")
    - b9f2b29b94 ("sched: Don't define sched_clock_irqtime as static key")
 
   The first one is a cherry-picked version of the second, and the first one
   is already upstream. ]
 
 Core & fair scheduler changes:
 
   - Cancel the slice protection of the idle entity (Zihan Zhou)
   - Reduce the default slice to avoid tasks getting an extra tick
     (Zihan Zhou)
   - Force propagating min_slice of cfs_rq when {en,de}queue tasks
     (Tianchen Ding)
   - Refactor can_migrate_task() to elimate looping (I Hsin Cheng)
   - Add unlikey branch hints to several system calls (Colin Ian King)
   - Optimize current_clr_polling() on certain architectures (Yujun Dong)
 
 Deadline scheduler: (Juri Lelli)
 
   - Remove redundant dl_clear_root_domain call
   - Move dl_rebuild_rd_accounting to cpuset.h
 
 Uclamp:
 
   - Use the uclamp_is_used() helper instead of open-coding it (Xuewen Yan)
   - Optimize sched_uclamp_used static key enabling (Xuewen Yan)
 
 Scheduler topology support: (Juri Lelli)
 
   - Ignore special tasks when rebuilding domains
   - Add wrappers for sched_domains_mutex
   - Generalize unique visiting of root domains
   - Rebuild root domain accounting after every update
   - Remove partition_and_rebuild_sched_domains
   - Stop exposing partition_sched_domains_locked
 
 RSEQ: (Michael Jeanson)
 
   - Update kernel fields in lockstep with CONFIG_DEBUG_RSEQ=y
   - Fix segfault on registration when rseq_cs is non-zero
   - selftests: Add rseq syscall errors test
   - selftests: Ensure the rseq ABI TLS is actually 1024 bytes
 
 Membarriers:
 
   - Fix redundant load of membarrier_state (Nysal Jan K.A.)
 
 Scheduler debugging:
 
   - Introduce and use preempt_model_str() (Sebastian Andrzej Siewior)
   - Make CONFIG_SCHED_DEBUG unconditional (Ingo Molnar)
 
 Fixes and cleanups:
 
   - Always save/restore x86 TSC sched_clock() on suspend/resume
    (Guilherme G. Piccoli)
 
   - Misc fixes and cleanups (Thorsten Blum, Juri Lelli,
     Sebastian Andrzej Siewior)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
 "Core & fair scheduler changes:

   - Cancel the slice protection of the idle entity (Zihan Zhou)
   - Reduce the default slice to avoid tasks getting an extra tick
     (Zihan Zhou)
   - Force propagating min_slice of cfs_rq when {en,de}queue tasks
     (Tianchen Ding)
   - Refactor can_migrate_task() to elimate looping (I Hsin Cheng)
   - Add unlikey branch hints to several system calls (Colin Ian King)
   - Optimize current_clr_polling() on certain architectures (Yujun
     Dong)

  Deadline scheduler: (Juri Lelli)
   - Remove redundant dl_clear_root_domain call
   - Move dl_rebuild_rd_accounting to cpuset.h

  Uclamp:
   - Use the uclamp_is_used() helper instead of open-coding it (Xuewen
     Yan)
   - Optimize sched_uclamp_used static key enabling (Xuewen Yan)

  Scheduler topology support: (Juri Lelli)
   - Ignore special tasks when rebuilding domains
   - Add wrappers for sched_domains_mutex
   - Generalize unique visiting of root domains
   - Rebuild root domain accounting after every update
   - Remove partition_and_rebuild_sched_domains
   - Stop exposing partition_sched_domains_locked

  RSEQ: (Michael Jeanson)
   - Update kernel fields in lockstep with CONFIG_DEBUG_RSEQ=y
   - Fix segfault on registration when rseq_cs is non-zero
   - selftests: Add rseq syscall errors test
   - selftests: Ensure the rseq ABI TLS is actually 1024 bytes

  Membarriers:
   - Fix redundant load of membarrier_state (Nysal Jan K.A.)

  Scheduler debugging:
   - Introduce and use preempt_model_str() (Sebastian Andrzej Siewior)
   - Make CONFIG_SCHED_DEBUG unconditional (Ingo Molnar)

  Fixes and cleanups:
   - Always save/restore x86 TSC sched_clock() on suspend/resume
     (Guilherme G. Piccoli)
   - Misc fixes and cleanups (Thorsten Blum, Juri Lelli, Sebastian
     Andrzej Siewior)"

* tag 'sched-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
  cpuidle, sched: Use smp_mb__after_atomic() in current_clr_polling()
  sched/debug: Remove CONFIG_SCHED_DEBUG
  sched/debug: Remove CONFIG_SCHED_DEBUG from self-test config files
  sched/debug, Documentation: Remove (most) CONFIG_SCHED_DEBUG references from documentation
  sched/debug: Make CONFIG_SCHED_DEBUG functionality unconditional
  sched/debug: Make 'const_debug' tunables unconditional __read_mostly
  sched/debug: Change SCHED_WARN_ON() to WARN_ON_ONCE()
  rseq/selftests: Fix namespace collision with rseq UAPI header
  include/{topology,cpuset}: Move dl_rebuild_rd_accounting to cpuset.h
  sched/topology: Stop exposing partition_sched_domains_locked
  cgroup/cpuset: Remove partition_and_rebuild_sched_domains
  sched/topology: Remove redundant dl_clear_root_domain call
  sched/deadline: Rebuild root domain accounting after every update
  sched/deadline: Generalize unique visiting of root domains
  sched/topology: Wrappers for sched_domains_mutex
  sched/deadline: Ignore special tasks when rebuilding domains
  tracing: Use preempt_model_str()
  xtensa: Rely on generic printing of preemption model
  x86: Rely on generic printing of preemption model
  s390: Rely on generic printing of preemption model
  ...
2025-03-24 21:28:12 -07:00
Gabriele Monaco
26f80681a0 sched: Add sched tracepoints for RV task model
Add the following tracepoints:
* sched_entry(bool preempt, ip)
    Called while entering __schedule
* sched_exit(bool is_switch, ip)
    Called while exiting __schedule
* sched_set_state(task, curr_state, state)
    Called when a task changes its state (to and from running)

These tracepoints are useful to describe the Linux task model and are
adapted from the patches by Daniel Bristot de Oliveira
(https://bristot.me/linux-task-model/).

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/20250305140406.350227-2-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-03-24 17:27:39 -04:00
Masami Hiramatsu (Google)
3cf67d61ff hung_task: show the blocker task if the task is hung on mutex
Patch series "hung_task: Dump the blocking task stacktrace", v4.

The hung_task detector is very useful for detecting the lockup.  However,
since it only dumps the blocked (uninterruptible sleep) processes, it is
not enough to identify the root cause of that lockup.

For example, if a process holds a mutex and sleep an event in
interruptible state long time, the other processes will wait on the mutex
in uninterruptible state.  In this case, the waiter processes are dumped,
but the blocker process is not shown because it is sleep in interruptible
state.

This adds a feature to dump the blocker task which holds a mutex
when detecting a hung task. e.g.

 INFO: task cat:115 blocked for more than 122 seconds.
       Not tainted 6.14.0-rc3-00003-ga8946be3de00 #156
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:cat             state:D stack:13432 pid:115   tgid:115   ppid:106    task_flags:0x400100 flags:0x00000002
 Call Trace:
  <TASK>
  __schedule+0x731/0x960
  ? schedule_preempt_disabled+0x54/0xa0
  schedule+0xb7/0x140
  ? __mutex_lock+0x51b/0xa60
  ? __mutex_lock+0x51b/0xa60
  schedule_preempt_disabled+0x54/0xa0
  __mutex_lock+0x51b/0xa60
  read_dummy+0x23/0x70
  full_proxy_read+0x6a/0xc0
  vfs_read+0xc2/0x340
  ? __pfx_direct_file_splice_eof+0x10/0x10
  ? do_sendfile+0x1bd/0x2e0
  ksys_read+0x76/0xe0
  do_syscall_64+0xe3/0x1c0
  ? exc_page_fault+0xa9/0x1d0
  entry_SYSCALL_64_after_hwframe+0x77/0x7f
 RIP: 0033:0x4840cd
 RSP: 002b:00007ffe99071828 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004840cd
 RDX: 0000000000001000 RSI: 00007ffe99071870 RDI: 0000000000000003
 RBP: 00007ffe99071870 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000001000000 R11: 0000000000000246 R12: 0000000000001000
 R13: 00000000132fd3a0 R14: 0000000000000001 R15: ffffffffffffffff
  </TASK>
 INFO: task cat:115 is blocked on a mutex likely owned by task cat:114.
 task:cat             state:S stack:13432 pid:114   tgid:114   ppid:106    task_flags:0x400100 flags:0x00000002
 Call Trace:
  <TASK>
  __schedule+0x731/0x960
  ? schedule_timeout+0xa8/0x120
  schedule+0xb7/0x140
  schedule_timeout+0xa8/0x120
  ? __pfx_process_timeout+0x10/0x10
  msleep_interruptible+0x3e/0x60
  read_dummy+0x2d/0x70
  full_proxy_read+0x6a/0xc0
  vfs_read+0xc2/0x340
  ? __pfx_direct_file_splice_eof+0x10/0x10
  ? do_sendfile+0x1bd/0x2e0
  ksys_read+0x76/0xe0
  do_syscall_64+0xe3/0x1c0
  ? exc_page_fault+0xa9/0x1d0
  entry_SYSCALL_64_after_hwframe+0x77/0x7f
 RIP: 0033:0x4840cd
 RSP: 002b:00007ffe3e0147b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004840cd
 RDX: 0000000000001000 RSI: 00007ffe3e014800 RDI: 0000000000000003
 RBP: 00007ffe3e014800 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000001000000 R11: 0000000000000246 R12: 0000000000001000
 R13: 000000001a0a93a0 R14: 0000000000000001 R15: ffffffffffffffff
  </TASK>

TBD: We can extend this feature to cover other locks like rwsem and
rt_mutex, but rwsem requires to dump all the tasks which acquire and wait
that rwsem.  We can follow the waiter link but the output will be a bit
different compared with mutex case.


This patch (of 2):

The "hung_task" shows a long-time uninterruptible slept task, but most
often, it's blocked on a mutex acquired by another task.  Without dumping
such a task, investigating the root cause of the hung task problem is very
difficult.

This introduce task_struct::blocker_mutex to point the mutex lock which
this task is waiting for.  Since the mutex has "owner" information, we can
find the owner task and dump it with hung tasks.

Note: the owner can be changed while dumping the owner task, so
this is "likely" the owner of the mutex.

With this change, the hung task shows blocker task's info like below;

 INFO: task cat:115 blocked for more than 122 seconds.
       Not tainted 6.14.0-rc3-00003-ga8946be3de00 #156
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:cat             state:D stack:13432 pid:115   tgid:115   ppid:106    task_flags:0x400100 flags:0x00000002
 Call Trace:
  <TASK>
  __schedule+0x731/0x960
  ? schedule_preempt_disabled+0x54/0xa0
  schedule+0xb7/0x140
  ? __mutex_lock+0x51b/0xa60
  ? __mutex_lock+0x51b/0xa60
  schedule_preempt_disabled+0x54/0xa0
  __mutex_lock+0x51b/0xa60
  read_dummy+0x23/0x70
  full_proxy_read+0x6a/0xc0
  vfs_read+0xc2/0x340
  ? __pfx_direct_file_splice_eof+0x10/0x10
  ? do_sendfile+0x1bd/0x2e0
  ksys_read+0x76/0xe0
  do_syscall_64+0xe3/0x1c0
  ? exc_page_fault+0xa9/0x1d0
  entry_SYSCALL_64_after_hwframe+0x77/0x7f
 RIP: 0033:0x4840cd
 RSP: 002b:00007ffe99071828 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004840cd
 RDX: 0000000000001000 RSI: 00007ffe99071870 RDI: 0000000000000003
 RBP: 00007ffe99071870 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000001000000 R11: 0000000000000246 R12: 0000000000001000
 R13: 00000000132fd3a0 R14: 0000000000000001 R15: ffffffffffffffff
  </TASK>
 INFO: task cat:115 is blocked on a mutex likely owned by task cat:114.
 task:cat             state:S stack:13432 pid:114   tgid:114   ppid:106    task_flags:0x400100 flags:0x00000002
 Call Trace:
  <TASK>
  __schedule+0x731/0x960
  ? schedule_timeout+0xa8/0x120
  schedule+0xb7/0x140
  schedule_timeout+0xa8/0x120
  ? __pfx_process_timeout+0x10/0x10
  msleep_interruptible+0x3e/0x60
  read_dummy+0x2d/0x70
  full_proxy_read+0x6a/0xc0
  vfs_read+0xc2/0x340
  ? __pfx_direct_file_splice_eof+0x10/0x10
  ? do_sendfile+0x1bd/0x2e0
  ksys_read+0x76/0xe0
  do_syscall_64+0xe3/0x1c0
  ? exc_page_fault+0xa9/0x1d0
  entry_SYSCALL_64_after_hwframe+0x77/0x7f
 RIP: 0033:0x4840cd
 RSP: 002b:00007ffe3e0147b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004840cd
 RDX: 0000000000001000 RSI: 00007ffe3e014800 RDI: 0000000000000003
 RBP: 00007ffe3e014800 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000001000000 R11: 0000000000000246 R12: 0000000000001000
 R13: 000000001a0a93a0 R14: 0000000000000001 R15: ffffffffffffffff
  </TASK>

[akpm@linux-foundation.org: implement debug_show_blocker() in C rather than in CPP]
Link: https://lkml.kernel.org/r/174046694331.2194069.15472952050240807469.stgit@mhiramat.tok.corp.google.com
Link: https://lkml.kernel.org/r/174046695384.2194069.16796289525958195643.stgit@mhiramat.tok.corp.google.com
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Will Deacon <will@kernel.org>
Cc: Yongliang Gao <leonylgao@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-21 22:10:04 -07:00
Juri Lelli
56209334dd sched/topology: Wrappers for sched_domains_mutex
Create wrappers for sched_domains_mutex so that it can transparently be
used on both CONFIG_SMP and !CONFIG_SMP, as some function will need to
do.

Fixes: 53916d5fd3 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MP5Oq9RB8jBs3y@jlelli-thinkpadt14gen4.remote.csb
2025-03-17 11:23:41 +01:00
Kan Liang
cb43691293 perf: Save PMU specific data in task_struct
Some PMU specific data has to be saved/restored during context switch,
e.g. LBR call stack data. Currently, the data is saved in event context
structure, but only for per-process event. For system-wide event,
because of missing the LBR call stack data after context switch, LBR
callstacks are always shorter in comparison to per-process mode.

For example,
  Per-process mode:
  $perf record --call-graph lbr -- taskset -c 0 ./tchain_edit

  -   99.90%    99.86%  tchain_edit  tchain_edit       [.] f3
       99.86% _start
          __libc_start_main
          generic_start_main
          main
          f1
        - f2
             f3

  System-wide mode:
  $perf record --call-graph lbr -a -- taskset -c 0 ./tchain_edit

  -   99.88%    99.82%  tchain_edit  tchain_edit        [.] f3
   - 62.02% main
        f1
        f2
        f3
   - 28.83% f1
      - f2
        f3
   - 28.83% f1
      - f2
           f3
   - 8.88% generic_start_main
        main
        f1
        f2
        f3

It isn't practical to simply allocate the data for system-wide event in
CPU context structure for all tasks. We have no idea which CPU a task
will be scheduled to. The duplicated LBR data has to be maintained on
every CPU context structure. That's a huge waste. Otherwise, the LBR
data still lost if the task is scheduled to another CPU.

Save the pmu specific data in task_struct. The size of pmu specific data
is 788 bytes for LBR call stack. Usually, the overall amount of threads
doesn't exceed a few thousands. For 10K threads, keeping LBR data would
consume additional ~8MB. The additional space will only be allocated
during LBR call stack monitoring. It will be released when the
monitoring is finished.

Furthermore, moving task_ctx_data from perf_event_context to task_struct
can reduce complexity and make things clearer. E.g. perf doesn't need to
swap task_ctx_data on optimized context switch path.
This patch set is just the first step. There could be other
optimization/extension on top of this patch set. E.g. for cgroup
profiling, perf just needs to save/store the LBR call stack information
for tasks in specific cgroup. That could reduce the additional space.
Also, the LBR call stack can be available for software events, or allow
even debugging use cases, like LBRs on crash later.

Because of the alignment requirement of Intel Arch LBR, the Kmem cache
is used to allocate the PMU specific data. It's required when child task
allocates the space. Save it in struct perf_ctx_data.
The refcount in struct perf_ctx_data is used to track the users of pmu
specific data.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Link: https://lore.kernel.org/r/20250314172700.438923-1-kan.liang@linux.intel.com
2025-03-17 11:23:36 +01:00
Mike Snitzer
ce6d9c1c2b NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback
Add PF_KCOMPACTD flag and current_is_kcompactd() helper to check for it so
nfs_release_folio() can skip calling nfs_wb_folio() from kcompactd.

Otherwise NFS can deadlock waiting for kcompactd enduced writeback which
recurses back to NFS (which triggers writeback to NFSD via NFS loopback
mount on the same host, NFSD blocks waiting for XFS's call to
__filemap_get_folio):

6070.550357] INFO: task kcompactd0:58 blocked for more than 4435 seconds.

{---
[58] "kcompactd0"
[<0>] folio_wait_bit+0xe8/0x200
[<0>] folio_wait_writeback+0x2b/0x80
[<0>] nfs_wb_folio+0x80/0x1b0 [nfs]
[<0>] nfs_release_folio+0x68/0x130 [nfs]
[<0>] split_huge_page_to_list_to_order+0x362/0x840
[<0>] migrate_pages_batch+0x43d/0xb90
[<0>] migrate_pages_sync+0x9a/0x240
[<0>] migrate_pages+0x93c/0x9f0
[<0>] compact_zone+0x8e2/0x1030
[<0>] compact_node+0xdb/0x120
[<0>] kcompactd+0x121/0x2e0
[<0>] kthread+0xcf/0x100
[<0>] ret_from_fork+0x31/0x40
[<0>] ret_from_fork_asm+0x1a/0x30
---}

[akpm@linux-foundation.org: fix build]
Link: https://lkml.kernel.org/r/20250225022002.26141-1-snitzer@kernel.org
Fixes: 96780ca55e ("NFS: fix up nfs_release_folio() to try to release the page")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-05 21:36:15 -08:00
Linus Torvalds
c159dfbdd4 Mainly individually changelogged singleton patches. The patch series in
this pull are:
 
 - "lib min_heap: Improve min_heap safety, testing, and documentation"
   from Kuan-Wei Chiu provides various tightenings to the min_heap library
   code.
 
 - "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms some
   cleanup and Rust preparation in the xarray library code.
 
 - "Update reference to include/asm-<arch>" from Geert Uytterhoeven fixes
   pathnames in some code comments.
 
 - "Converge on using secs_to_jiffies()" from Easwar Hariharan uses the
   new secs_to_jiffies() in various places where that is appropriate.
 
 - "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen
   switches two filesystems to the new mount API.
 
 - "Convert ocfs2 to use folios" from Matthew Wilcox does that.
 
 - "Remove get_task_comm() and print task comm directly" from Yafang Shao
   removes now-unneeded calls to get_task_comm() in various places.
 
 - "squashfs: reduce memory usage and update docs" from Phillip Lougher
   implements some memory savings in squashfs and performs some
   maintainability work.
 
 - "lib: clarify comparison function requirements" from Kuan-Wei Chiu
   tightens the sort code's behaviour and adds some maintenance work.
 
 - "nilfs2: protect busy buffer heads from being force-cleared" from
   Ryusuke Konishi fixes an issues in nlifs when the fs is presented with a
   corrupted image.
 
 - "nilfs2: fix kernel-doc comments for function return values" from
   Ryusuke Konishi fixes some nilfs kerneldoc.
 
 - "nilfs2: fix issues with rename operations" from Ryusuke Konishi
   addresses some nilfs BUG_ONs which syzbot was able to trigger.
 
 - "minmax.h: Cleanups and minor optimisations" from David Laight
   does some maintenance work on the min/max library code.
 
 - "Fixes and cleanups to xarray" from Kemeng Shi does maintenance work
   on the xarray library code.
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Merge tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:
 "Mainly individually changelogged singleton patches. The patch series
  in this pull are:

   - "lib min_heap: Improve min_heap safety, testing, and documentation"
     from Kuan-Wei Chiu provides various tightenings to the min_heap
     library code

   - "xarray: extract __xa_cmpxchg_raw" from Tamir Duberstein preforms
     some cleanup and Rust preparation in the xarray library code

   - "Update reference to include/asm-<arch>" from Geert Uytterhoeven
     fixes pathnames in some code comments

   - "Converge on using secs_to_jiffies()" from Easwar Hariharan uses
     the new secs_to_jiffies() in various places where that is
     appropriate

   - "ocfs2, dlmfs: convert to the new mount API" from Eric Sandeen
     switches two filesystems to the new mount API

   - "Convert ocfs2 to use folios" from Matthew Wilcox does that

   - "Remove get_task_comm() and print task comm directly" from Yafang
     Shao removes now-unneeded calls to get_task_comm() in various
     places

   - "squashfs: reduce memory usage and update docs" from Phillip
     Lougher implements some memory savings in squashfs and performs
     some maintainability work

   - "lib: clarify comparison function requirements" from Kuan-Wei Chiu
     tightens the sort code's behaviour and adds some maintenance work

   - "nilfs2: protect busy buffer heads from being force-cleared" from
     Ryusuke Konishi fixes an issues in nlifs when the fs is presented
     with a corrupted image

   - "nilfs2: fix kernel-doc comments for function return values" from
     Ryusuke Konishi fixes some nilfs kerneldoc

   - "nilfs2: fix issues with rename operations" from Ryusuke Konishi
     addresses some nilfs BUG_ONs which syzbot was able to trigger

   - "minmax.h: Cleanups and minor optimisations" from David Laight does
     some maintenance work on the min/max library code

   - "Fixes and cleanups to xarray" from Kemeng Shi does maintenance
     work on the xarray library code"

* tag 'mm-nonmm-stable-2025-01-24-23-16' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (131 commits)
  ocfs2: use str_yes_no() and str_no_yes() helper functions
  include/linux/lz4.h: add some missing macros
  Xarray: use xa_mark_t in xas_squash_marks() to keep code consistent
  Xarray: remove repeat check in xas_squash_marks()
  Xarray: distinguish large entries correctly in xas_split_alloc()
  Xarray: move forward index correctly in xas_pause()
  Xarray: do not return sibling entries from xas_find_marked()
  ipc/util.c: complete the kernel-doc function descriptions
  gcov: clang: use correct function param names
  latencytop: use correct kernel-doc format for func params
  minmax.h: remove some #defines that are only expanded once
  minmax.h: simplify the variants of clamp()
  minmax.h: move all the clamp() definitions after the min/max() ones
  minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
  minmax.h: reduce the #define expansion of min(), max() and clamp()
  minmax.h: update some comments
  minmax.h: add whitespace around operators and after commas
  nilfs2: do not update mtime of renamed directory that is not moved
  nilfs2: handle errors that nilfs_prepare_chunk() may return
  CREDITS: fix spelling mistake
  ...
2025-01-26 17:50:53 -08:00
Linus Torvalds
62de6e1685 Scheduler enhancements for v6.14:
- Fair scheduler (SCHED_FAIR) enhancements:
 
    - Behavioral improvements:
      - Untangle NEXT_BUDDY and pick_next_task() (Peter Zijlstra)
 
    - Delayed-dequeue enhancements & fixes: (Vincent Guittot)
 
      - Rename h_nr_running into h_nr_queued
      - Add new cfs_rq.h_nr_runnable
      - Use the new cfs_rq.h_nr_runnable
      - Removed unsued cfs_rq.h_nr_delayed
      - Rename cfs_rq.idle_h_nr_running into h_nr_idle
      - Remove unused cfs_rq.idle_nr_running
      - Rename cfs_rq.nr_running into nr_queued
      - Do not try to migrate delayed dequeue task
      - Fix variable declaration position
      - Encapsulate set custom slice in a __setparam_fair() function
 
    - Fixes:
      - Fix race between yield_to() and try_to_wake_up() (Tianchen Ding)
      - Fix CPU bandwidth limit bypass during CPU hotplug (Vishal Chourasia)
 
    - Cleanups:
      - Clean up in migrate_degrades_locality() to improve
        readability (Peter Zijlstra)
      - Mark m*_vruntime() with __maybe_unused (Andy Shevchenko)
      - Update comments after sched_tick() rename (Sebastian Andrzej Siewior)
      - Remove CONFIG_CFS_BANDWIDTH=n definition of cfs_bandwidth_used()
        (Valentin Schneider)
 
  - Deadline scheduler (SCHED_DL) enhancements:
 
    - Restore dl_server bandwidth on non-destructive root domain
      changes (Juri Lelli)
 
    - Correctly account for allocated bandwidth during
      hotplug (Juri Lelli)
 
    - Check bandwidth overflow earlier for hotplug (Juri Lelli)
 
    - Clean up goto label in pick_earliest_pushable_dl_task()
      (John Stultz)
 
    - Consolidate timer cancellation (Wander Lairson Costa)
 
  - Load-balancer enhancements:
 
    - Improve performance by prioritizing migrating eligible
      tasks in sched_balance_rq() (Hao Jia)
 
    - Do not compute NUMA Balancing stats unnecessarily during
      load-balancing (K Prateek Nayak)
 
    - Do not compute overloaded status unnecessarily during
      load-balancing (K Prateek Nayak)
 
  - Generic scheduling code enhancements:
 
    - Use READ_ONCE() in task_on_rq_queued(), to consistently use
      the WRITE_ONCE() updated ->on_rq field (Harshit Agarwal)
 
  - Isolated CPUs support enhancements: (Waiman Long)
 
    - Make "isolcpus=nohz" equivalent to "nohz_full"
    - Consolidate housekeeping cpumasks that are always identical
    - Remove HK_TYPE_SCHED
    - Unify HK_TYPE_{TIMER|TICK|MISC} to HK_TYPE_KERNEL_NOISE
 
  - RSEQ enhancements:
 
    - Validate read-only fields under DEBUG_RSEQ config
      (Mathieu Desnoyers)
 
  - PSI enhancements:
 
    - Fix race when task wakes up before psi_sched_switch()
      adjusts flags (Chengming Zhou)
 
  - IRQ time accounting performance enhancements: (Yafang Shao)
 
    - Define sched_clock_irqtime as static key
    - Don't account irq time if sched_clock_irqtime is disabled
 
  - Virtual machine scheduling enhancements:
 
    - Don't try to catch up excess steal time (Suleiman Souhlal)
 
  - Heterogenous x86 CPU scheduling enhancements: (K Prateek Nayak)
 
    - Convert "sysctl_sched_itmt_enabled" to boolean
    - Use guard() for itmt_update_mutex
    - Move the "sched_itmt_enabled" sysctl to debugfs
    - Remove x86_smt_flags and use cpu_smt_flags directly
    - Use x86_sched_itmt_flags for PKG domain unconditionally
 
  - Debugging code & instrumentation enhancements:
 
    - Change need_resched warnings to pr_err() (David Rientjes)
    - Print domain name in /proc/schedstat (K Prateek Nayak)
    - Fix value reported by hot tasks pulled in /proc/schedstat (Peter Zijlstra)
    - Report the different kinds of imbalances in /proc/schedstat (Swapnil Sapkal)
    - Move sched domain name out of CONFIG_SCHED_DEBUG (Swapnil Sapkal)
    - Update Schedstat version to 17 (Swapnil Sapkal)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
 "Fair scheduler (SCHED_FAIR) enhancements:

   - Behavioral improvements:
      - Untangle NEXT_BUDDY and pick_next_task() (Peter Zijlstra)

   - Delayed-dequeue enhancements & fixes: (Vincent Guittot)
      - Rename h_nr_running into h_nr_queued
      - Add new cfs_rq.h_nr_runnable
      - Use the new cfs_rq.h_nr_runnable
      - Removed unsued cfs_rq.h_nr_delayed
      - Rename cfs_rq.idle_h_nr_running into h_nr_idle
      - Remove unused cfs_rq.idle_nr_running
      - Rename cfs_rq.nr_running into nr_queued
      - Do not try to migrate delayed dequeue task
      - Fix variable declaration position
      - Encapsulate set custom slice in a __setparam_fair() function

   - Fixes:
      - Fix race between yield_to() and try_to_wake_up() (Tianchen Ding)
      - Fix CPU bandwidth limit bypass during CPU hotplug (Vishal
        Chourasia)

   - Cleanups:
      - Clean up in migrate_degrades_locality() to improve readability
        (Peter Zijlstra)
      - Mark m*_vruntime() with __maybe_unused (Andy Shevchenko)
      - Update comments after sched_tick() rename (Sebastian Andrzej
        Siewior)
      - Remove CONFIG_CFS_BANDWIDTH=n definition of cfs_bandwidth_used()
        (Valentin Schneider)

  Deadline scheduler (SCHED_DL) enhancements:

   - Restore dl_server bandwidth on non-destructive root domain changes
     (Juri Lelli)

   - Correctly account for allocated bandwidth during hotplug (Juri
     Lelli)

   - Check bandwidth overflow earlier for hotplug (Juri Lelli)

   - Clean up goto label in pick_earliest_pushable_dl_task() (John
     Stultz)

   - Consolidate timer cancellation (Wander Lairson Costa)

  Load-balancer enhancements:

   - Improve performance by prioritizing migrating eligible tasks in
     sched_balance_rq() (Hao Jia)

   - Do not compute NUMA Balancing stats unnecessarily during
     load-balancing (K Prateek Nayak)

   - Do not compute overloaded status unnecessarily during
     load-balancing (K Prateek Nayak)

  Generic scheduling code enhancements:

   - Use READ_ONCE() in task_on_rq_queued(), to consistently use the
     WRITE_ONCE() updated ->on_rq field (Harshit Agarwal)

  Isolated CPUs support enhancements: (Waiman Long)

   - Make "isolcpus=nohz" equivalent to "nohz_full"
   - Consolidate housekeeping cpumasks that are always identical
   - Remove HK_TYPE_SCHED
   - Unify HK_TYPE_{TIMER|TICK|MISC} to HK_TYPE_KERNEL_NOISE

  RSEQ enhancements:

   - Validate read-only fields under DEBUG_RSEQ config (Mathieu
     Desnoyers)

  PSI enhancements:

   - Fix race when task wakes up before psi_sched_switch() adjusts flags
     (Chengming Zhou)

  IRQ time accounting performance enhancements: (Yafang Shao)

   - Define sched_clock_irqtime as static key
   - Don't account irq time if sched_clock_irqtime is disabled

  Virtual machine scheduling enhancements:

   - Don't try to catch up excess steal time (Suleiman Souhlal)

  Heterogenous x86 CPU scheduling enhancements: (K Prateek Nayak)

   - Convert "sysctl_sched_itmt_enabled" to boolean
   - Use guard() for itmt_update_mutex
   - Move the "sched_itmt_enabled" sysctl to debugfs
   - Remove x86_smt_flags and use cpu_smt_flags directly
   - Use x86_sched_itmt_flags for PKG domain unconditionally

  Debugging code & instrumentation enhancements:

   - Change need_resched warnings to pr_err() (David Rientjes)
   - Print domain name in /proc/schedstat (K Prateek Nayak)
   - Fix value reported by hot tasks pulled in /proc/schedstat (Peter
     Zijlstra)
   - Report the different kinds of imbalances in /proc/schedstat
     (Swapnil Sapkal)
   - Move sched domain name out of CONFIG_SCHED_DEBUG (Swapnil Sapkal)
   - Update Schedstat version to 17 (Swapnil Sapkal)"

* tag 'sched-core-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
  rseq: Fix rseq unregistration regression
  psi: Fix race when task wakes up before psi_sched_switch() adjusts flags
  sched, psi: Don't account irq time if sched_clock_irqtime is disabled
  sched: Don't account irq time if sched_clock_irqtime is disabled
  sched: Define sched_clock_irqtime as static key
  sched/fair: Do not compute overloaded status unnecessarily during lb
  sched/fair: Do not compute NUMA Balancing stats unnecessarily during lb
  x86/topology: Use x86_sched_itmt_flags for PKG domain unconditionally
  x86/topology: Remove x86_smt_flags and use cpu_smt_flags directly
  x86/itmt: Move the "sched_itmt_enabled" sysctl to debugfs
  x86/itmt: Use guard() for itmt_update_mutex
  x86/itmt: Convert "sysctl_sched_itmt_enabled" to boolean
  sched/core: Prioritize migrating eligible tasks in sched_balance_rq()
  sched/debug: Change need_resched warnings to pr_err
  sched/fair: Encapsulate set custom slice in a __setparam_fair() function
  sched: Fix race between yield_to() and try_to_wake_up()
  docs: Update Schedstat version to 17
  sched/stats: Print domain name in /proc/schedstat
  sched: Move sched domain name out of CONFIG_SCHED_DEBUG
  sched: Report the different kinds of imbalances in /proc/schedstat
  ...
2025-01-21 11:32:36 -08:00
Linus Torvalds
fadc3ed9ce execve updates for v6.14-rc1
- exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case
   (Tycho Andersen, Kees Cook)
 
 - binfmt_misc: Fix comment typos (Christophe JAILLET)
 
 - exec: move empty argv[0] warning closer to actual logic (Nir Lichtman)
 
 - exec: remove legacy custom binfmt modules autoloading (Nir Lichtman)
 
 - binfmt_flat: Fix integer overflow bug on 32 bit systems (Dan Carpenter)
 
 - exec: Make sure set_task_comm() always NUL-terminates
 
 - coredump: Do not lock when copying "comm"
 
 - MAINTAINERS: add auxvec.h and set myself as maintainer
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Merge tag 'execve-v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull execve updates from Kees Cook:

 - fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case (Tycho
   Andersen, Kees Cook)

 - binfmt_misc: Fix comment typos (Christophe JAILLET)

 - move empty argv[0] warning closer to actual logic (Nir Lichtman)

 - remove legacy custom binfmt modules autoloading (Nir Lichtman)

 - Make sure set_task_comm() always NUL-terminates

 - binfmt_flat: Fix integer overflow bug on 32 bit systems (Dan
   Carpenter)

 - coredump: Do not lock when copying "comm"

 - MAINTAINERS: add auxvec.h and set myself as maintainer

* tag 'execve-v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  binfmt_flat: Fix integer overflow bug on 32 bit systems
  selftests/exec: add a test for execveat()'s comm
  exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case
  exec: Make sure task->comm is always NUL-terminated
  exec: remove legacy custom binfmt modules autoloading
  exec: move warning of null argv to be next to the relevant code
  fs: binfmt: Fix a typo
  MAINTAINERS: exec: Mark Kees as maintainer
  MAINTAINERS: exec: Add auxvec.h UAPI
  coredump: Do not lock during 'comm' reporting
2025-01-20 13:27:58 -08:00
Wang Yaxin
f65c64f311 delayacct: add delay min to record delay peak
Delay accounting can now calculate the average delay of processes, detect
the overall system load, and also record the 'delay max' to identify
potential abnormal delays.  However, 'delay min' can help us identify
another useful delay peak.  By comparing the difference between 'delay
max' and 'delay min', we can understand the optimization space for
latency, providing a reference for the optimization of latency
performance.

Use case
=========
bash-4.4# ./getdelays -d -t 242
print delayacct stats ON
TGID    242
CPU         count     real total  virtual total    delay total  delay average      delay max      delay min
               39      156000000      156576579        2111069          0.054ms     0.212296ms     0.031307ms
IO          count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
SWAP        count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
RECLAIM     count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
THRASHING   count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
COMPACT     count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms
WPCOPY      count    delay total  delay average      delay max      delay min
              156       11215873          0.072ms     0.207403ms     0.033913ms
IRQ         count    delay total  delay average      delay max      delay min
                0              0          0.000ms     0.000000ms     0.000000ms

Link: https://lkml.kernel.org/r/20241220173105906EOdsPhzjMLYNJJBqgz1ga@zte.com.cn
Co-developed-by: Wang Yong <wang.yong12@zte.com.cn>
Signed-off-by: Wang Yong <wang.yong12@zte.com.cn>
Co-developed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Co-developed-by: Kun Jiang <jiang.kun2@zte.com.cn>
Signed-off-by: Kun Jiang <jiang.kun2@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Peilin He <he.peilin@zte.com.cn>
Cc: tuqiang <tu.qiang35@zte.com.cn>
Cc: ye xingchen <ye.xingchen@zte.com.cn>
Cc: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-12 20:21:16 -08:00
Wang Yaxin
658eb5ab91 delayacct: add delay max to record delay peak
Introduce the use cases of delay max, which can help quickly detect
potential abnormal delays in the system and record the types and specific
details of delay spikes.

Problem
========
Delay accounting can track the average delay of processes to show
system workload. However, when a process experiences a significant
delay, maybe a delay spike, which adversely affects performance,
getdelays can only display the average system delay over a period
of time. Yet, average delay is unhelpful for diagnosing delay peak.
It is not even possible to determine which type of delay has spiked,
as this information might be masked by the average delay.

Solution
=========
the 'delay max' can display delay peak since the system's startup,
which can record potential abnormal delays over time, including
the type of delay and the maximum delay. This is helpful for
quickly identifying crash caused by delay.

Use case
=========
bash# ./getdelays -d -p 244
print delayacct stats ON
PID     244

CPU             count     real total  virtual total    delay total  delay average      delay max
                   68      192000000      213676651         705643          0.010ms     0.306381ms
IO              count    delay total  delay average      delay max
                    0              0          0.000ms     0.000000ms
SWAP            count    delay total  delay average      delay max
                    0              0          0.000ms     0.000000ms
RECLAIM         count    delay total  delay average      delay max
                    0              0          0.000ms     0.000000ms
THRASHING       count    delay total  delay average      delay max
                    0              0          0.000ms     0.000000ms
COMPACT         count    delay total  delay average      delay max
                    0              0          0.000ms     0.000000ms
WPCOPY          count    delay total  delay average      delay max
                  235       15648284          0.067ms     0.263842ms
IRQ             count    delay total  delay average      delay max
                    0              0          0.000ms     0.000000ms

[wang.yaxin@zte.com.cn: update docs and fix some spelling errors]
  Link: https://lkml.kernel.org/r/20241213192700771XKZ8H30OtHSeziGqRVMs0@zte.com.cn
Link: https://lkml.kernel.org/r/20241203164848805CS62CQPQWG9GLdQj2_BxS@zte.com.cn
Co-developed-by: Wang Yong <wang.yong12@zte.com.cn>
Signed-off-by: Wang Yong <wang.yong12@zte.com.cn>
Co-developed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Co-developed-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Kun Jiang <jiang.kun2@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Peilin He <he.peilin@zte.com.cn>
Cc: tuqiang <tu.qiang35@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: ye xingchen <ye.xingchen@zte.com.cn>
Cc: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-12 20:20:59 -08:00
Chen Ridong
f718faf394 freezer, sched: Report frozen tasks as 'D' instead of 'R'
Before commit:

  f5d39b0208 ("freezer,sched: Rewrite core freezer logic")

the frozen task stat was reported as 'D' in cgroup v1.

However, after rewriting the core freezer logic, the frozen task stat is
reported as 'R'. This is confusing, especially when a task with stat of
'S' is frozen.

This bug can be reproduced with these steps:

	$ cd /sys/fs/cgroup/freezer/
	$ mkdir test
	$ sleep 1000 &
	[1] 739         // task whose stat is 'S'
	$ echo 739 > test/cgroup.procs
	$ echo FROZEN > test/freezer.state
	$ ps -aux | grep 739
	root     739  0.1  0.0   8376  1812 pts/0    R    10:56   0:00 sleep 1000

As shown above, a task whose stat is 'S' was changed to 'R' when it was
frozen.

To solve this regression, simply maintain the same reported state as
before the rewrite.

[ mingo: Enhanced the changelog and comments ]

Fixes: f5d39b0208 ("freezer,sched: Rewrite core freezer logic")
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Koutný <mkoutny@suse.com>
Link: https://lore.kernel.org/r/20241217004818.3200515-1-chenridong@huaweicloud.com
2024-12-29 10:14:20 +01:00
Peter Zijlstra
a430d99e34 sched/fair: Fix value reported by hot tasks pulled in /proc/schedstat
In /proc/schedstat, lb_hot_gained reports the number hot tasks pulled
during load balance. This value is incremented in can_migrate_task()
if the task is migratable and hot. After incrementing the value,
load balancer can still decide not to migrate this task leading to wrong
accounting. Fix this by incrementing stats when hot tasks are detached.
This issue only exists in detach_tasks() where we can decide to not
migrate hot task even if it is migratable. However, in detach_one_task(),
we migrate it unconditionally.

[Swapnil: Handled the case where nr_failed_migrations_hot was not accounted properly and wrote commit log]

Fixes: d31980846f ("sched: Move up affinity check to mitigate useless redoing overhead")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: "Gautham R. Shenoy" <gautham.shenoy@amd.com>
Not-yet-signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241220063224.17767-2-swapnil.sapkal@amd.com
2024-12-20 15:31:16 +01:00
Kees Cook
3a3f61ce5e exec: Make sure task->comm is always NUL-terminated
Using strscpy() meant that the final character in task->comm may be
non-NUL for a moment before the "string too long" truncation happens.

Instead of adding a new use of the ambiguous strncpy(), we'd want to
use memtostr_pad() which enforces being able to check at compile time
that sizes are sensible, but this requires being able to see string
buffer lengths. Instead of trying to inline __set_task_comm() (which
needs to call trace and perf functions), just open-code it. But to
make sure we're always safe, add compile-time checking like we already
do for get_task_comm().

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Kees Cook <kees@kernel.org>
2024-12-16 16:53:00 -08:00
Vineeth Pillai (Google)
b53127db1d sched/dlserver: Fix dlserver double enqueue
dlserver can get dequeued during a dlserver pick_task due to the delayed
deueue feature and this can lead to issues with dlserver logic as it
still thinks that dlserver is on the runqueue. The dlserver throttling
and replenish logic gets confused and can lead to double enqueue of
dlserver.

Double enqueue of dlserver could happend due to couple of reasons:

Case 1
------

Delayed dequeue feature[1] can cause dlserver being stopped during a
pick initiated by dlserver:
  __pick_next_task
   pick_task_dl -> server_pick_task
    pick_task_fair
     pick_next_entity (if (sched_delayed))
      dequeue_entities
       dl_server_stop

server_pick_task goes ahead with update_curr_dl_se without knowing that
dlserver is dequeued and this confuses the logic and may lead to
unintended enqueue while the server is stopped.

Case 2
------
A race condition between a task dequeue on one cpu and same task's enqueue
on this cpu by a remote cpu while the lock is released causing dlserver
double enqueue.

One cpu would be in the schedule() and releasing RQ-lock:

current->state = TASK_INTERRUPTIBLE();
        schedule();
          deactivate_task()
            dl_stop_server();
          pick_next_task()
            pick_next_task_fair()
              sched_balance_newidle()
                rq_unlock(this_rq)

at which point another CPU can take our RQ-lock and do:

        try_to_wake_up()
          ttwu_queue()
            rq_lock()
            ...
            activate_task()
              dl_server_start() --> first enqueue
            wakeup_preempt() := check_preempt_wakeup_fair()
              update_curr()
                update_curr_task()
                  if (current->dl_server)
                    dl_server_update()
                      enqueue_dl_entity() --> second enqueue

This bug was not apparent as the enqueue in dl_server_start doesn't
usually happen because of the defer logic. But as a side effect of the
first case(dequeue during dlserver pick), dl_throttled and dl_yield will
be set and this causes the time accounting of dlserver to messup and
then leading to a enqueue in dl_server_start.

Have an explicit flag representing the status of dlserver to avoid the
confusion. This is set in dl_server_start and reset in dlserver_stop.

Fixes: 63ba8422f8 ("sched/deadline: Introduce deadline servers")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: "Vineeth Pillai (Google)" <vineeth@bitbyteword.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@codethink.co.uk> # ROCK 5B
Link: https://lkml.kernel.org/r/20241213032244.877029-1-vineeth@bitbyteword.org
2024-12-13 12:57:34 +01:00
Mathieu Desnoyers
7d5265ffcd rseq: Validate read-only fields under DEBUG_RSEQ config
The rseq uapi requires cooperation between users of the rseq fields
to ensure that all libraries and applications using rseq within a
process do not interfere with each other.

This is especially important for fields which are meant to be read-only
from user-space, as documented in uapi/linux/rseq.h:

  - cpu_id_start,
  - cpu_id,
  - node_id,
  - mm_cid.

Storing to those fields from a user-space library prevents any sharing
of the rseq ABI with other libraries and applications, as other users
are not aware that the content of those fields has been altered by a
third-party library.

This is unfortunately the current behavior of tcmalloc: it purposefully
overlaps part of a cached value with the cpu_id_start upper bits to get
notified about preemption, because the kernel clears those upper bits
before returning to user-space. This behavior does not conform to the
rseq uapi header ABI.

This prevents tcmalloc from using rseq when rseq is registered by the
GNU C library 2.35+. It requires tcmalloc users to disable glibc rseq
registration with a glibc tunable, which is a sad state of affairs.

Considering that tcmalloc and the GNU C library are the two first
upstream projects using rseq, and that they are already incompatible due
to use of this hack, adding kernel-level validation of all read-only
fields content is necessary to ensure future users of rseq abide by the
rseq ABI requirements.

Validate that user-space does not corrupt the read-only fields and
conform to the rseq uapi header ABI when the kernel is built with
CONFIG_DEBUG_RSEQ=y. This is done by storing a copy of the read-only
fields in the task_struct, and validating the prior values present in
user-space before updating them. If the values do not match, print
a warning on the console (printk_ratelimited()).

This is a first step to identify misuses of the rseq ABI by printing
a warning on the console. After a giving some time to userspace to
correct its use of rseq, the plan is to eventually terminate offending
processes with SIGSEGV.

This change is expected to produce warnings for the upstream tcmalloc
implementation, but tcmalloc developers mentioned they were open to
adapt their implementation to kernel-level change.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://github.com/google/tcmalloc/issues/144
2024-12-10 15:07:06 +01:00
Linus Torvalds
f5f4745a7f - The series "resource: A couple of cleanups" from Andy Shevchenko
performs some cleanups in the resource management code.
 
 - The series "Improve the copy of task comm" from Yafang Shao addresses
   possible race-induced overflows in the management of task_struct.comm[].
 
 - The series "Remove unnecessary header includes from
   {tools/}lib/list_sort.c" from Kuan-Wei Chiu adds some cleanups and a
   small fix to the list_sort library code and to its selftest.
 
 - The series "Enhance min heap API with non-inline functions and
   optimizations" also from Kuan-Wei Chiu optimizes and cleans up the
   min_heap library code.
 
 - The series "nilfs2: Finish folio conversion" from Ryusuke Konishi
   finishes off nilfs2's folioification.
 
 - The series "add detect count for hung tasks" from Lance Yang adds more
   userspace visibility into the hung-task detector's activity.
 
 - Apart from that, singelton patches in many places - please see the
   individual changelogs for details.
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Merge tag 'mm-nonmm-stable-2024-11-24-02-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - The series "resource: A couple of cleanups" from Andy Shevchenko
   performs some cleanups in the resource management code

 - The series "Improve the copy of task comm" from Yafang Shao addresses
   possible race-induced overflows in the management of
   task_struct.comm[]

 - The series "Remove unnecessary header includes from
   {tools/}lib/list_sort.c" from Kuan-Wei Chiu adds some cleanups and a
   small fix to the list_sort library code and to its selftest

 - The series "Enhance min heap API with non-inline functions and
   optimizations" also from Kuan-Wei Chiu optimizes and cleans up the
   min_heap library code

 - The series "nilfs2: Finish folio conversion" from Ryusuke Konishi
   finishes off nilfs2's folioification

 - The series "add detect count for hung tasks" from Lance Yang adds
   more userspace visibility into the hung-task detector's activity

 - Apart from that, singelton patches in many places - please see the
   individual changelogs for details

* tag 'mm-nonmm-stable-2024-11-24-02-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (71 commits)
  gdb: lx-symbols: do not error out on monolithic build
  kernel/reboot: replace sprintf() with sysfs_emit()
  lib: util_macros_kunit: add kunit test for util_macros.h
  util_macros.h: fix/rework find_closest() macros
  Improve consistency of '#error' directive messages
  ocfs2: fix uninitialized value in ocfs2_file_read_iter()
  hung_task: add docs for hung_task_detect_count
  hung_task: add detect count for hung tasks
  dma-buf: use atomic64_inc_return() in dma_buf_getfile()
  fs/proc/kcore.c: fix coccinelle reported ERROR instances
  resource: avoid unnecessary resource tree walking in __region_intersects()
  ocfs2: remove unused errmsg function and table
  ocfs2: cluster: fix a typo
  lib/scatterlist: use sg_phys() helper
  checkpatch: always parse orig_commit in fixes tag
  nilfs2: convert metadata aops from writepage to writepages
  nilfs2: convert nilfs_recovery_copy_block() to take a folio
  nilfs2: convert nilfs_page_count_clean_buffers() to take a folio
  nilfs2: remove nilfs_writepage
  nilfs2: convert checkpoint file to be folio-based
  ...
2024-11-25 16:09:48 -08:00
Linus Torvalds
aad3a0d084 ftrace updates for v6.13:
- Merged tag ftrace-v6.12-rc4
 
   There was a fix to locking in register_ftrace_graph() for shadow stacks
   that was sent upstream. But this code was also being rewritten, and the
   locking fix was needed. Merging this fix was required to continue the
   work.
 
 - Restructure the function graph shadow stack to prepare it for use with
   kretprobes
 
   With the goal of merging the shadow stack logic of function graph and
   kretprobes, some more restructuring of the function shadow stack is
   required.
 
   Move out function graph specific fields from the fgraph infrastructure and
   store it on the new stack variables that can pass data from the entry
   callback to the exit callback.
 
   Hopefully, with this change, the merge of kretprobes to use fgraph shadow
   stacks will be ready by the next merge window.
 
 - Make shadow stack 4k instead of using PAGE_SIZE.
 
   Some architectures have very large PAGE_SIZE values which make its use for
   shadow stacks waste a lot of memory.
 
 - Give shadow stacks its own kmem cache.
 
   When function graph is started, every task on the system gets a shadow
   stack. In the future, shadow stacks may not be 4K in size. Have it have
   its own kmem cache so that whatever size it becomes will still be
   efficient in allocations.
 
 - Initialize profiler graph ops as it will be needed for new updates to fgraph
 
 - Convert to use guard(mutex) for several ftrace and fgraph functions
 
 - Add more comments and documentation
 
 - Show function return address in function graph tracer
 
   Add an option to show the caller of a function at each entry of the
   function graph tracer, similar to what the function tracer does.
 
 - Abstract out ftrace_regs from being used directly like pt_regs
 
   ftrace_regs was created to store a partial pt_regs. It holds only the
   registers and stack information to get to the function arguments and
   return values. On several archs, it is simply a wrapper around pt_regs.
   But some users would access ftrace_regs directly to get the pt_regs which
   will not work on all archs. Make ftrace_regs an abstract structure that
   requires all access to its fields be through accessor functions.
 
 - Show how long it takes to do function code modifications
 
   When code modification for function hooks happen, it always had the time
   recorded in how long it took to do the conversion. But this value was
   never exported. Recently the code was touched due to new ROX modification
   handling that caused a large slow down in doing the modifications and
   had a significant impact on boot times.
 
   Expose the timings in the dyn_ftrace_total_info file. This file was
   created a while ago to show information about memory usage and such to
   implement dynamic function tracing. It's also an appropriate file to store
   the timings of this modification as well. This will make it easier to see
   the impact of changes to code modification on boot up timings.
 
 - Other clean ups and small fixes
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Merge tag 'ftrace-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ftrace updates from Steven Rostedt:

 - Restructure the function graph shadow stack to prepare it for use
   with kretprobes

   With the goal of merging the shadow stack logic of function graph and
   kretprobes, some more restructuring of the function shadow stack is
   required.

   Move out function graph specific fields from the fgraph
   infrastructure and store it on the new stack variables that can pass
   data from the entry callback to the exit callback.

   Hopefully, with this change, the merge of kretprobes to use fgraph
   shadow stacks will be ready by the next merge window.

 - Make shadow stack 4k instead of using PAGE_SIZE.

   Some architectures have very large PAGE_SIZE values which make its
   use for shadow stacks waste a lot of memory.

 - Give shadow stacks its own kmem cache.

   When function graph is started, every task on the system gets a
   shadow stack. In the future, shadow stacks may not be 4K in size.
   Have it have its own kmem cache so that whatever size it becomes will
   still be efficient in allocations.

 - Initialize profiler graph ops as it will be needed for new updates to
   fgraph

 - Convert to use guard(mutex) for several ftrace and fgraph functions

 - Add more comments and documentation

 - Show function return address in function graph tracer

   Add an option to show the caller of a function at each entry of the
   function graph tracer, similar to what the function tracer does.

 - Abstract out ftrace_regs from being used directly like pt_regs

   ftrace_regs was created to store a partial pt_regs. It holds only the
   registers and stack information to get to the function arguments and
   return values. On several archs, it is simply a wrapper around
   pt_regs. But some users would access ftrace_regs directly to get the
   pt_regs which will not work on all archs. Make ftrace_regs an
   abstract structure that requires all access to its fields be through
   accessor functions.

 - Show how long it takes to do function code modifications

   When code modification for function hooks happen, it always had the
   time recorded in how long it took to do the conversion. But this
   value was never exported. Recently the code was touched due to new
   ROX modification handling that caused a large slow down in doing the
   modifications and had a significant impact on boot times.

   Expose the timings in the dyn_ftrace_total_info file. This file was
   created a while ago to show information about memory usage and such
   to implement dynamic function tracing. It's also an appropriate file
   to store the timings of this modification as well. This will make it
   easier to see the impact of changes to code modification on boot up
   timings.

 - Other clean ups and small fixes

* tag 'ftrace-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (22 commits)
  ftrace: Show timings of how long nop patching took
  ftrace: Use guard to take ftrace_lock in ftrace_graph_set_hash()
  ftrace: Use guard to take the ftrace_lock in release_probe()
  ftrace: Use guard to lock ftrace_lock in cache_mod()
  ftrace: Use guard for match_records()
  fgraph: Use guard(mutex)(&ftrace_lock) for unregister_ftrace_graph()
  fgraph: Give ret_stack its own kmem cache
  fgraph: Separate size of ret_stack from PAGE_SIZE
  ftrace: Rename ftrace_regs_return_value to ftrace_regs_get_return_value
  selftests/ftrace: Fix check of return value in fgraph-retval.tc test
  ftrace: Use arch_ftrace_regs() for ftrace_regs_*() macros
  ftrace: Consolidate ftrace_regs accessor functions for archs using pt_regs
  ftrace: Make ftrace_regs abstract from direct use
  fgragh: No need to invoke the function call_filter_check_discard()
  fgraph: Simplify return address printing in function graph tracer
  function_graph: Remove unnecessary initialization in ftrace_graph_ret_addr()
  function_graph: Support recording and printing the function return address
  ftrace: Have calltime be saved in the fgraph storage
  ftrace: Use a running sleeptime instead of saving on shadow stack
  fgraph: Use fgraph data to store subtime for profiler
  ...
2024-11-20 11:34:10 -08:00
Linus Torvalds
0892d74213 x86/splitlock changes for v6.13:
- Move Split and Bus lock code to a dedicated file (Ravi Bangoria)
  - Add split/bus lock support for AMD (Ravi Bangoria)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-splitlock-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 splitlock updates from Ingo Molnar:

 - Move Split and Bus lock code to a dedicated file (Ravi Bangoria)

 - Add split/bus lock support for AMD (Ravi Bangoria)

* tag 'x86-splitlock-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/bus_lock: Add support for AMD
  x86/split_lock: Move Split and Bus lock code to a dedicated file
2024-11-19 14:34:02 -08:00
Yafang Shao
4cc0473d77 get rid of __get_task_comm()
Patch series "Improve the copy of task comm", v8.

Using {memcpy,strncpy,strcpy,kstrdup} to copy the task comm relies on the
length of task comm.  Changes in the task comm could result in a
destination string that is overflow.  Therefore, we should explicitly
ensure the destination string is always NUL-terminated, regardless of the
task comm.  This approach will facilitate future extensions to the task
comm.

As suggested by Linus [0], we can identify all relevant code with the
following git grep command:

  git grep 'memcpy.*->comm\>'
  git grep 'kstrdup.*->comm\>'
  git grep 'strncpy.*->comm\>'
  git grep 'strcpy.*->comm\>'

PATCH #2~#4:   memcpy
PATCH #5~#6:   kstrdup
PATCH #7:      strcpy

Please note that strncpy() is not included in this series as it is being
tracked by another effort. [1]


This patch (of 7):

We want to eliminate the use of __get_task_comm() for the following
reasons:

- The task_lock() is unnecessary
  Quoted from Linus [0]:
  : Since user space can randomly change their names anyway, using locking
  : was always wrong for readers (for writers it probably does make sense
  : to have some lock - although practically speaking nobody cares there
  : either, but at least for a writer some kind of race could have
  : long-term mixed results

Link: https://lkml.kernel.org/r/20241007144911.27693-1-laoar.shao@gmail.com
Link: https://lkml.kernel.org/r/20241007144911.27693-2-laoar.shao@gmail.com
Link: https://lore.kernel.org/all/CAHk-=wivfrF0_zvf+oj6==Sh=-npJooP8chLPEfaFV0oNYTTBA@mail.gmail.com [0]
Link: https://lore.kernel.org/all/CAHk-=whWtUC-AjmGJveAETKOMeMFSTwKwu99v7+b6AyHMmaDFA@mail.gmail.com/
Link: https://lore.kernel.org/all/CAHk-=wjAmmHUg6vho1KjzQi2=psR30+CogFd4aXrThr2gsiS4g@mail.gmail.com/ [0]
Link: https://github.com/KSPP/linux/issues/90 [1]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Matus Jokay <matus.jokay@stuba.sk>
Cc: Alejandro Colomar <alx@kernel.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Quentin Monnet <qmo@kernel.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-05 17:12:28 -08:00
Peter Zijlstra
26baa1f1c4 sched: Add TIF_NEED_RESCHED_LAZY infrastructure
Add the basic infrastructure to split the TIF_NEED_RESCHED bit in two.
Either bit will cause a resched on return-to-user, but only
TIF_NEED_RESCHED will drive IRQ preemption.

No behavioural change intended.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20241007075055.219540785@infradead.org
2024-11-05 12:55:37 +01:00
Ingo Molnar
d1fb8a78b2 Linux 6.12-rc4
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Merge tag 'v6.12-rc4' into sched/core, to resolve conflict

Overlapping fixes solving the same bug slightly differently:

  7266f0a6d3 fs/bcachefs: Fix __wait_on_freeing_inode() definition of waitqueue entry
  3b80552e70 bcachefs: __wait_for_freeing_inode: Switch to wait_bit_queue_entry

Use the upstream version.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-10-21 08:14:15 +02:00
Ingo Molnar
be602cde65 Merge branch 'linus' into sched/urgent, to resolve conflict
Conflicts:
	kernel/sched/ext.c

There's a context conflict between this upstream commit:

  3fdb9ebcec sched_ext: Start schedulers with consistent p->scx.slice values

... and this fix in sched/urgent:

  98442f0ccd sched: Fix delayed_dequeue vs switched_from_fair()

Resolve it.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-10-17 09:58:07 +02:00
Peter Zijlstra
3144c83dcc Merge branch 'tip/sched/urgent'
Sync with sched/urgent to avoid conflicts.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
2024-10-14 12:52:39 +02:00
Peter Zijlstra
cd9626e9eb sched/fair: Fix external p->on_rq users
Sean noted that ever since commit 152e11f6df ("sched/fair: Implement
delayed dequeue") KVM's preemption notifiers have started
mis-classifying preemption vs blocking.

Notably p->on_rq is no longer sufficient to determine if a task is
runnable or blocked -- the aforementioned commit introduces tasks that
remain on the runqueue even through they will not run again, and
should be considered blocked for many cases.

Add the task_is_runnable() helper to classify things and audit all
external users of the p->on_rq state. Also add a few comments.

Fixes: 152e11f6df ("sched/fair: Implement delayed dequeue")
Reported-by: Sean Christopherson <seanjc@google.com>
Tested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20241010091843.GK33184@noisy.programming.kicks-ass.net
2024-10-14 09:14:35 +02:00
Michal Hocko
9a8da05d7a Revert "mm: introduce PF_MEMALLOC_NORECLAIM, PF_MEMALLOC_NOWARN"
This reverts commit eab0af905b.

There is no existing user of those flags.  PF_MEMALLOC_NOWARN is dangerous
because a nested allocation context can use GFP_NOFAIL which could cause
unexpected failure.  Such a code would be hard to maintain because it
could be deeper in the call chain.

PF_MEMALLOC_NORECLAIM has been added even when it was pointed out [1] that
such a allocation contex is inherently unsafe if the context doesn't fully
control all allocations called from this context.

While PF_MEMALLOC_NOWARN is not dangerous the way PF_MEMALLOC_NORECLAIM is
it doesn't have any user and as Matthew has pointed out we are running out
of those flags so better reclaim it without any real users.

[1] https://lore.kernel.org/all/ZcM0xtlKbAOFjv5n@tiehlicka/

Link: https://lkml.kernel.org/r/20240926172940.167084-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: James Morris <jmorris@namei.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-09 12:47:19 -07:00
David Disseldorp
5e9f0c4819 sched: remove unused __HAVE_THREAD_FUNCTIONS hook support
__HAVE_THREAD_FUNCTIONS could be defined by architectures wishing to
provide their own task_thread_info(), task_stack_page(),
setup_thread_stack() and end_of_stack() hooks.

Commit cf8e865810 ("arch: Remove Itanium (IA-64) architecture")
removed the last upstream consumer of __HAVE_THREAD_FUNCTIONS, so change
the remaining !CONFIG_THREAD_INFO_IN_TASK && !__HAVE_THREAD_FUNCTIONS
conditionals to only check for the former case.

Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lkml.kernel.org/r/20240930050945.30304-2-ddiss@suse.de
2024-10-07 09:28:40 +02:00
Steven Rostedt
3c9880f3ab ftrace: Use a running sleeptime instead of saving on shadow stack
The fgraph "sleep-time" option tells the function graph tracer and the
profiler whether to include the time a function "sleeps" (is scheduled off
the CPU) in its duration for the function. By default it is true, which
means the duration of a function is calculated by the timestamp of when the
function was entered to the timestamp of when it exits.

If the "sleep-time" option is disabled, it needs to remove the time that the
task was not running on the CPU during the function. Currently it is done in
a sched_switch tracepoint probe where it moves the "calltime" (time of entry
of the function) forward by the sleep time calculated. It updates all the
calltime in the shadow stack.

This is time consuming for those users of the function graph tracer that
does not care about the sleep time. Instead, add a "ftrace_sleeptime" to the
task_struct that gets the sleep time added each time the task wakes up. Then
have the function entry save the current "ftrace_sleeptime" and on function
exit, move the calltime forward by the difference of the current
"ftrace_sleeptime" from the saved sleeptime.

This removes one dependency of "calltime" needed to be on the shadow stack.
It also simplifies the code that removes the sleep time of functions.

TODO: Only enable the sched_switch tracepoint when this is needed.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Link: https://lore.kernel.org/20240914214826.938908568@goodmis.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-09-30 11:12:46 -04:00
Linus Torvalds
88264981f2 sched_ext: Initial pull request for v6.12
This is the initial pull request of sched_ext. The v7 patchset
 (https://lkml.kernel.org/r/20240618212056.2833381-1-tj@kernel.org) is
 applied on top of tip/sched/core + bpf/master as of Jun 18th.
 
   tip/sched/core 793a62823d1c ("sched/core: Drop spinlocks on contention iff kernel is preempti
 ble")
   bpf/master f6afdaf72a ("Merge branch 'bpf-support-resilient-split-btf'")
 
 Since then, the following pulls were made:
 
 - v6.11-rc1 is pulled to keep up with the mainline.
 
 - tip/sched/core was pulled several times:
 
   - 7b9f6c864a, 0df340ceae, 5ac998574f, 0b1777f0fa04: To resolve
     conflicts. See each commit for details on conflicts and their
     resolutions.
 
   - d7b01aef9dbd: To receive fd03c5b858 ("sched: Rework pick_next_task()")
     and related commits. @prev in added to sched_class->put_prev_task() and
     put_prev_task() is reordered after ->pick_task(), which makes
     sched_class->switch_class() unnecessary. The follow-up commits update
     sched_ext accordingly and drop sched_class->switch_class().
 
 - bpf/master was pulled to receive baebe9aaba ("bpf: allow passing struct
   bpf_iter_<type> as kfunc arguments") and related changes in preparation
   for the DSQ iterator patchset
 
 To obtain the net sched_ext changes, diff against:
 
   git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git for-6.12-base
 
 which is the merge of:
 
   tip/sched/core bc9057da1a ("sched/cpufreq: Use NSEC_PER_MSEC for deadline task")
   bpf/master 2ad6d23f46 ("selftests/bpf: Do not update vmlinux.h unnecessarily")
 
 Since the v7 patchset, the following changes were made:
 
 - cpuperf support which was a part of the v6 patchset was posted separately
   and then applied after reviews.
 
 - cgroup support which was a part of the v6 patchset was posted seprately,
   iterated and then applied.
 
 - Improve integration with sched core.
 
 - Double locking usage in migration paths dropped. Depend on
   TASK_ON_RQ_MIGRATING synchronization instead.
 
 - The BPF scheduler couldn't directly dispatch to the local DSQ of another
   CPU using a SCX_DSQ_LOCAL_ON verdict. This caused difficulties around
   handling non-wakeup enqueues. Updated so that SCX_DSQ_LOCAL_ON can be used
   in the enqueue path too.
 
 - DSQ iterator which was a part of the v6 patchset was posted separately.
   The iterator itself was applied after a couple revisions. The associated
   selective consumption kfunc can use further improvements and is still
   being worked on.
 
 - scx_bpf_dispatch[_vtime]_from_dsq() added to increase flexibility. A task
   can now be transferred between two DSQs from almost any context. This
   involved significant refactoring of migration code.
 
 - Various fixes and improvements.
 
 As the branch is based on top of tip/sched/core + bpf/master, please merge
 after both are applied.
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Merge tag 'sched_ext-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

Pull sched_ext support from Tejun Heo:
 "This implements a new scheduler class called ‘ext_sched_class’, or
  sched_ext, which allows scheduling policies to be implemented as BPF
  programs.

  The goals of this are:

   - Ease of experimentation and exploration: Enabling rapid iteration
     of new scheduling policies.

   - Customization: Building application-specific schedulers which
     implement policies that are not applicable to general-purpose
     schedulers.

   - Rapid scheduler deployments: Non-disruptive swap outs of scheduling
     policies in production environments"

See individual commits for more documentation, but also the cover letter
for the latest series:

Link: https://lore.kernel.org/all/20240618212056.2833381-1-tj@kernel.org/

* tag 'sched_ext-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (110 commits)
  sched: Move update_other_load_avgs() to kernel/sched/pelt.c
  sched_ext: Don't trigger ops.quiescent/runnable() on migrations
  sched_ext: Synchronize bypass state changes with rq lock
  scx_qmap: Implement highpri boosting
  sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()
  sched_ext: Compact struct bpf_iter_scx_dsq_kern
  sched_ext: Replace consume_local_task() with move_local_task_to_local_dsq()
  sched_ext: Move consume_local_task() upward
  sched_ext: Move sanity check and dsq_mod_nr() into task_unlink_from_dsq()
  sched_ext: Reorder args for consume_local/remote_task()
  sched_ext: Restructure dispatch_to_local_dsq()
  sched_ext: Fix processs_ddsp_deferred_locals() by unifying DTL_INVALID handling
  sched_ext: Make find_dsq_for_dispatch() handle SCX_DSQ_LOCAL_ON
  sched_ext: Refactor consume_remote_task()
  sched_ext: Rename scx_kfunc_set_sleepable to unlocked and relocate
  sched_ext: Add missing static to scx_dump_data
  sched_ext: Add missing static to scx_has_op[]
  sched_ext: Temporarily work around pick_task_scx() being called without balance_scx()
  sched_ext: Add a cgroup scheduler which uses flattened hierarchy
  sched_ext: Add cgroup support
  ...
2024-09-21 09:44:57 -07:00
Linus Torvalds
2004cef11e In the v6.12 scheduler development cycle we had 63 commits from 18 contributors:
- Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot de Oliveira's
    last major contribution to the kernel:
 
      "SCHED_DEADLINE servers can help fixing starvation issues of low priority
      tasks (e.g., SCHED_OTHER) when higher priority tasks monopolize CPU
      cycles. Today we have RT Throttling; DEADLINE servers should be able to
      replace and improve that."
 
      (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes,
       Youssef Esmat, Huang Shijie)
 
  - Preparatory changes for sched_ext integration:
 
      - Use set_next_task(.first) where required
      - Fix up set_next_task() implementations
      - Clean up DL server vs. core sched
      - Split up put_prev_task_balance()
      - Rework pick_next_task()
      - Combine the last put_prev_task() and the first set_next_task()
      - Rework dl_server
      - Add put_prev_task(.next)
 
       (Peter Zijlstra, with a fix by Tejun Heo)
 
  - Complete the EEVDF transition and refine EEVDF scheduling:
 
      - Implement delayed dequeue
      - Allow shorter slices to wakeup-preempt
      - Use sched_attr::sched_runtime to set request/slice suggestion
      - Document the new feature flags
      - Remove unused and duplicate-functionality fields
      - Simplify & unify pick_next_task_fair()
      - Misc debuggability enhancements
 
       (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann,
        Valentin Schneider and Chuyi Zhou)
 
  - Initialize the vruntime of a new task when it is first enqueued,
    resulting in significant decrease in latency of newly woken tasks.
    (Zhang Qiao)
 
  - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
    (K Prateek Nayak, Peter Zijlstra)
 
  - Clean up and clarify the usage of Clean up usage of rt_task()
    (Qais Yousef)
 
  - Preempt SCHED_IDLE entities in strict cgroup hierarchies
    (Tianchen Ding)
 
  - Clarify the documentation of time units for deadline scheduler
    parameters. (Christian Loehle)
 
  - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
    the original change seems to be working fine.
    (Phil Auld)
 
  - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
    Peilin He, Qais Yousefm and Vincent Guittot)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot
   de Oliveira's last major contribution to the kernel:

     "SCHED_DEADLINE servers can help fixing starvation issues of low
      priority tasks (e.g., SCHED_OTHER) when higher priority tasks
      monopolize CPU cycles. Today we have RT Throttling; DEADLINE
      servers should be able to replace and improve that."

   (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes, Youssef
   Esmat, Huang Shijie)

 - Preparatory changes for sched_ext integration:
     - Use set_next_task(.first) where required
     - Fix up set_next_task() implementations
     - Clean up DL server vs. core sched
     - Split up put_prev_task_balance()
     - Rework pick_next_task()
     - Combine the last put_prev_task() and the first set_next_task()
     - Rework dl_server
     - Add put_prev_task(.next)

   (Peter Zijlstra, with a fix by Tejun Heo)

 - Complete the EEVDF transition and refine EEVDF scheduling:
     - Implement delayed dequeue
     - Allow shorter slices to wakeup-preempt
     - Use sched_attr::sched_runtime to set request/slice suggestion
     - Document the new feature flags
     - Remove unused and duplicate-functionality fields
     - Simplify & unify pick_next_task_fair()
     - Misc debuggability enhancements

   (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann, Valentin
   Schneider and Chuyi Zhou)

 - Initialize the vruntime of a new task when it is first enqueued,
   resulting in significant decrease in latency of newly woken tasks
   (Zhang Qiao)

 - Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
   (K Prateek Nayak, Peter Zijlstra)

 - Clean up and clarify the usage of Clean up usage of rt_task()
   (Qais Yousef)

 - Preempt SCHED_IDLE entities in strict cgroup hierarchies
   (Tianchen Ding)

 - Clarify the documentation of time units for deadline scheduler
   parameters (Christian Loehle)

 - Remove the HZ_BW chicken-bit feature flag introduced a year ago,
   the original change seems to be working fine (Phil Auld)

 - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
   Peilin He, Qais Yousefm and Vincent Guittot)

* tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
  sched/cpufreq: Use NSEC_PER_MSEC for deadline task
  cpufreq/cppc: Use NSEC_PER_MSEC for deadline task
  sched/deadline: Clarify nanoseconds in uapi
  sched/deadline: Convert schedtool example to chrt
  sched/debug: Fix the runnable tasks output
  sched: Fix sched_delayed vs sched_core
  kernel/sched: Fix util_est accounting for DELAY_DEQUEUE
  kthread: Fix task state in kthread worker if being frozen
  sched/pelt: Use rq_clock_task() for hw_pressure
  sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c
  sched/core: Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
  sched: Add put_prev_task(.next)
  sched: Rework dl_server
  sched: Combine the last put_prev_task() and the first set_next_task()
  sched: Rework pick_next_task()
  sched: Split up put_prev_task_balance()
  sched: Clean up DL server vs core sched
  sched: Fixup set_next_task() implementations
  sched: Use set_next_task(.first) where required
  sched/fair: Properly deactivate sched_delayed task upon class change
  ...
2024-09-19 15:55:58 +02:00
Tejun Heo
d7b01aef9d Merge branch 'tip/sched/core' into for-6.12
- Resolve trivial context conflicts from dl_server clearing being moved
  around.

- Add @next to put_prev_task_scx() and @prev to pick_next_task_scx() to
  match sched/core.

- Merge sched_class->switch_class() addition from sched_ext with
  tip/sched/core changes in __pick_next_task().

- Make pick_next_task_scx() call put_prev_task_scx() to emulate the previous
  behavior where sched_class->put_prev_task() was called before
  sched_class->pick_next_task().

While this makes sched_ext build and function, the behavior is not in line
with other sched classes. The follow-up patches will address the
discrepancies and remove sched_class->switch_class().

Signed-off-by: Tejun Heo <tj@kernel.org>
2024-09-03 12:49:18 -10:00
Peter Zijlstra
4686cc598f sched: Clean up DL server vs core sched
Abide by the simple rule:

  pick_next_task() := pick_task() + set_next_task(.first = true)

This allows us to trivially get rid of server_pick_next() and things
collapse nicely.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240813224015.837303391@infradead.org
2024-09-03 15:26:31 +02:00
Tejun Heo
5ac998574f Merge branch 'tip/sched/core' into for-6.12
To receive 863ccdbb91 ("sched: Allow sched_class::dequeue_task() to fail")
which makes sched_class.dequeue_task() return bool instead of void. This
leads to compile breakage and will be fixed by a follow-up patch.

Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-20 08:55:26 -10:00
Peter Zijlstra
aef6987d89 sched/eevdf: Propagate min_slice up the cgroup hierarchy
In the absence of an explicit cgroup slice configureation, make mixed
slice length work with cgroups by propagating the min_slice up the
hierarchy.

This ensures the cgroup entity gets timely service to service its
entities that have this timing constraint set on them.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lkml.kernel.org/r/20240727105030.948188417@infradead.org
2024-08-17 11:06:46 +02:00
Peter Zijlstra
857b158dc5 sched/eevdf: Use sched_attr::sched_runtime to set request/slice suggestion
Allow applications to directly set a suggested request/slice length using
sched_attr::sched_runtime.

The implementation clamps the value to: 0.1[ms] <= slice <= 100[ms]
which is 1/10 the size of HZ=1000 and 10 times the size of HZ=100.

Applications should strive to use their periodic runtime at a high
confidence interval (95%+) as the target slice. Using a smaller slice
will introduce undue preemptions, while using a larger value will
increase latency.

For all the following examples assume a scheduling quantum of 8, and for
consistency all examples have W=4:

  {A,B,C,D}(w=1,r=8):

  ABCD...
  +---+---+---+---

  t=0, V=1.5				t=1, V=3.5
  A  |------<				A          |------<
  B   |------<				B   |------<
  C    |------<				C    |------<
  D     |------<			D     |------<
  ---+*------+-------+---		---+--*----+-------+---

  t=2, V=5.5				t=3, V=7.5
  A          |------<			A          |------<
  B           |------<			B           |------<
  C    |------<				C            |------<
  D     |------<			D     |------<
  ---+----*--+-------+---		---+------*+-------+---

Note: 4 identical tasks in FIFO order

~~~

  {A,B}(w=1,r=16) C(w=2,r=16)

  AACCBBCC...
  +---+---+---+---

  t=0, V=1.25				t=2, V=5.25
  A  |--------------<                   A                  |--------------<
  B   |--------------<                  B   |--------------<
  C    |------<                         C    |------<
  ---+*------+-------+---               ---+----*--+-------+---

  t=4, V=8.25				t=6, V=12.25
  A                  |--------------<   A                  |--------------<
  B   |--------------<                  B                   |--------------<
  C            |------<                 C            |------<
  ---+-------*-------+---               ---+-------+---*---+---

Note: 1 heavy task -- because q=8, double r such that the deadline of the w=2
      task doesn't go below q.

Note: observe the full schedule becomes: W*max(r_i/w_i) = 4*2q = 8q in length.

Note: the period of the heavy task is half the full period at:
      W*(r_i/w_i) = 4*(2q/2) = 4q

~~~

  {A,C,D}(w=1,r=16) B(w=1,r=8):

  BAACCBDD...
  +---+---+---+---

  t=0, V=1.5				t=1, V=3.5
  A  |--------------<			A  |---------------<
  B   |------<				B           |------<
  C    |--------------<			C    |--------------<
  D     |--------------<		D     |--------------<
  ---+*------+-------+---		---+--*----+-------+---

  t=3, V=7.5				t=5, V=11.5
  A                  |---------------<  A                  |---------------<
  B           |------<                  B           |------<
  C    |--------------<                 C                    |--------------<
  D     |--------------<                D     |--------------<
  ---+------*+-------+---               ---+-------+--*----+---

  t=6, V=13.5
  A                  |---------------<
  B                   |------<
  C                    |--------------<
  D     |--------------<
  ---+-------+----*--+---

Note: 1 short task -- again double r so that the deadline of the short task
      won't be below q. Made B short because its not the leftmost task, but is
      eligible with the 0,1,2,3 spread.

Note: like with the heavy task, the period of the short task observes:
      W*(r_i/w_i) = 4*(1q/1) = 4q

~~~

  A(w=1,r=16) B(w=1,r=8) C(w=2,r=16)

  BCCAABCC...
  +---+---+---+---

  t=0, V=1.25				t=1, V=3.25
  A  |--------------<                   A  |--------------<
  B   |------<                          B           |------<
  C    |------<                         C    |------<
  ---+*------+-------+---               ---+--*----+-------+---

  t=3, V=7.25				t=5, V=11.25
  A  |--------------<                   A                  |--------------<
  B           |------<                  B           |------<
  C            |------<                 C            |------<
  ---+------*+-------+---               ---+-------+--*----+---

  t=6, V=13.25
  A                  |--------------<
  B                   |------<
  C            |------<
  ---+-------+----*--+---

Note: 1 heavy and 1 short task -- combine them all.

Note: both the short and heavy task end up with a period of 4q

~~~

  A(w=1,r=16) B(w=2,r=16) C(w=1,r=8)

  BBCAABBC...
  +---+---+---+---

  t=0, V=1				t=2, V=5
  A  |--------------<                   A  |--------------<
  B   |------<                          B           |------<
  C    |------<                         C    |------<
  ---+*------+-------+---               ---+----*--+-------+---

  t=3, V=7				t=5, V=11
  A  |--------------<                   A                  |--------------<
  B           |------<                  B           |------<
  C            |------<                 C            |------<
  ---+------*+-------+---               ---+-------+--*----+---

  t=7, V=15
  A                  |--------------<
  B                   |------<
  C            |------<
  ---+-------+------*+---

Note: as before but permuted

~~~

From all this it can be deduced that, for the steady state:

 - the total period (P) of a schedule is:	W*max(r_i/w_i)
 - the average period of a task is:		W*(r_i/w_i)
 - each task obtains the fair share:		w_i/W of each full period P

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lkml.kernel.org/r/20240727105030.842834421@infradead.org
2024-08-17 11:06:45 +02:00
Peter Zijlstra
82e9d0456e sched/fair: Avoid re-setting virtual deadline on 'migrations'
During OSPM24 Youssef noted that migrations are re-setting the virtual
deadline. Notably everything that does a dequeue-enqueue, like setting
nice, changing preferred numa-node, and a myriad of other random crap,
will cause this to happen.

This shouldn't be. Preserve the relative virtual deadline across such
dequeue/enqueue cycles.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Tested-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lkml.kernel.org/r/20240727105030.625119246@infradead.org
2024-08-17 11:06:45 +02:00
Peter Zijlstra
a1c446611e sched,freezer: Mark TASK_FROZEN special
The special task states are those that do not suffer spurious wakeups,
TASK_FROZEN is very much one of those, mark it as such.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Tested-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lkml.kernel.org/r/20240727105029.998329901@infradead.org
2024-08-17 11:06:44 +02:00
Peter Zijlstra
abc158c82a sched: Prepare generic code for delayed dequeue
While most of the delayed dequeue code can be done inside the
sched_class itself, there is one location where we do not have an
appropriate hook, namely ttwu_runnable().

Add an ENQUEUE_DELAYED call to the on_rq path to deal with waking
delayed dequeue tasks.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Tested-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lkml.kernel.org/r/20240727105029.200000445@infradead.org
2024-08-17 11:06:42 +02:00
Ravi Bangoria
350afa8a11 x86/split_lock: Move Split and Bus lock code to a dedicated file
Bus Lock Detect functionality on AMD platforms works identical to Intel.

Move split_lock and bus_lock specific code from intel.c to a dedicated
file so that it can be compiled and supported on non-Intel platforms.

Also, introduce CONFIG_X86_BUS_LOCK_DETECT, make it dependent on
CONFIG_CPU_SUP_INTEL and add compilation dependency of the new bus_lock.c
file on CONFIG_X86_BUS_LOCK_DETECT.

Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/all/20240808062937.1149-2-ravi.bangoria@amd.com
2024-08-08 18:02:15 +02:00
Tejun Heo
0df340ceae Merge branch 'sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into for-6.12
Pull tip/sched/core to resolve the following four conflicts. While 2-4 are
simple context conflicts, 1 is a bit subtle and easy to resolve incorrectly.

1. 2c8d046d5d ("sched: Add normal_policy()")
   vs.
   faa42d2941 ("sched/fair: Make SCHED_IDLE entity be preempted in strict hierarchy")

The former converts direct test on p->policy to use the helper
normal_policy(). The latter moves the p->policy test to a different
location. Resolve by converting the test on p->plicy in the new location to
use normal_policy().

2. a7a9fc5492 ("sched_ext: Add boilerplate for extensible scheduler class")
   vs.
   a110a81c52 ("sched/deadline: Deferrable dl server")

Both add calls to put_prev_task_idle() and set_next_task_idle(). Simple
context conflict. Resolve by taking changes from both.

3. a7a9fc5492 ("sched_ext: Add boilerplate for extensible scheduler class")
   vs.
   c245910049 ("sched/core: Add clearing of ->dl_server in put_prev_task_balance()")

The former changes for_each_class() itertion to use for_each_active_class().
The latter moves away the adjacent dl_server handling code. Simple context
conflict. Resolve by taking changes from both.

4. 60c27fb59f ("sched_ext: Implement sched_ext_ops.cpu_online/offline()")
   vs.
   31b164e2e4 ("sched/smt: Introduce sched_smt_present_inc/dec() helper")
   2f02735412 ("sched/core: Introduce sched_set_rq_on/offline() helper")

The former adds scx_rq_deactivate() call. The latter two change code around
it. Simple context conflict. Resolve by taking changes from both.

Signed-off-by: Tejun Heo <tj@kernel.org>
2024-08-04 07:36:54 -10:00