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Rafael J. Wysocki 2075ccfcba cpufreq/sched: Explicitly synchronize limits_changed flag handling
[ Upstream commit 79443a7e9d ]

The handling of the limits_changed flag in struct sugov_policy needs to
be explicitly synchronized to ensure that cpufreq policy limits updates
will not be missed in some cases.

Without that synchronization it is theoretically possible that
the limits_changed update in sugov_should_update_freq() will be
reordered with respect to the reads of the policy limits in
cpufreq_driver_resolve_freq() and in that case, if the limits_changed
update in sugov_limits() clobbers the one in sugov_should_update_freq(),
the new policy limits may not take effect for a long time.

Likewise, the limits_changed update in sugov_limits() may theoretically
get reordered with respect to the updates of the policy limits in
cpufreq_set_policy() and if sugov_should_update_freq() runs between
them, the policy limits change may be missed.

To ensure that the above situations will not take place, add memory
barriers preventing the reordering in question from taking place and
add READ_ONCE() and WRITE_ONCE() annotations around all of the
limits_changed flag updates to prevent the compiler from messing up
with that code.

Fixes: 600f5badb7 ("cpufreq: schedutil: Don't skip freq update when limits change")
Cc: 5.3+ <stable@vger.kernel.org> # 5.3+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/3376719.44csPzL39Z@rjwysocki.net
[ Adjust context ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-09-09 18:45:22 +02:00
arch arm64: dts: rockchip: Add vcc-supply to SPI flash on rk3399-pinebook-pro 2025-09-09 18:45:18 +02:00
block block: don't call rq_qos_ops->done_bio if the bio isn't tracked 2025-08-28 16:22:54 +02:00
certs
crypto crypto: xts - Only add ecb if it is not already there 2025-06-27 11:04:01 +01:00
Documentation asm-generic: Add memory barrier dma_mb() 2025-08-28 16:22:57 +02:00
drivers e1000e: fix heap overflow in e1000_set_eeprom 2025-09-09 18:45:21 +02:00
fs xfs: do not propagate ENODATA disk errors into xattr code 2025-09-04 14:41:46 +02:00
include atm: atmtcp: Prevent arbitrary write in atmtcp_recv_control(). 2025-09-04 14:41:42 +02:00
init bpf: Clean up sockmap related Kconfigs 2025-06-27 11:04:09 +01:00
io_uring io_uring: fix possible deadlock in io_register_iowq_max_workers() 2024-11-17 14:59:39 +01:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:04:14 +01:00
kernel cpufreq/sched: Explicitly synchronize limits_changed flag handling 2025-09-09 18:45:22 +02:00
lib lib: test_objagg: Set error message in check_expect_hints_stats() 2025-07-17 18:27:47 +02:00
LICENSES
mm mm/slub: avoid accessing metadata when pointer is invalid in object_err() 2025-09-09 18:45:22 +02:00
net batman-adv: fix OOB read/write in network-coding decode 2025-09-09 18:45:21 +02:00
samples samples: mei: Fix building on musl libc 2025-08-28 16:22:32 +02:00
scripts kconfig: lxdialog: fix 'space' to (de)select options 2025-08-28 16:22:47 +02:00
security securityfs: don't pin dentries twice, once is enough... 2025-08-28 16:22:40 +02:00
sound ALSA: usb-audio: Add mute TLV for playback volumes on some devices 2025-09-09 18:45:20 +02:00
tools selftests: mptcp: pm: check flush doesn't reset limits 2025-08-28 16:22:58 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-06-27 11:04:11 +01:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-10-22 15:39:24 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-10-17 15:07:59 +02:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS platform: Add Surface platform directory 2025-06-27 11:04:19 +01:00
Makefile Linux 5.10.242 2025-09-04 14:41:46 +02:00
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