linux-yocto/mm
Gavin Guo ef5706bed9 mm/huge_memory: fix dereferencing invalid pmd migration entry
commit be6e843fc5 upstream.

When migrating a THP, concurrent access to the PMD migration entry during
a deferred split scan can lead to an invalid address access, as
illustrated below.  To prevent this invalid access, it is necessary to
check the PMD migration entry and return early.  In this context, there is
no need to use pmd_to_swp_entry and pfn_swap_entry_to_page to verify the
equality of the target folio.  Since the PMD migration entry is locked, it
cannot be served as the target.

Mailing list discussion and explanation from Hugh Dickins: "An anon_vma
lookup points to a location which may contain the folio of interest, but
might instead contain another folio: and weeding out those other folios is
precisely what the "folio != pmd_folio((*pmd)" check (and the "risk of
replacing the wrong folio" comment a few lines above it) is for."

BUG: unable to handle page fault for address: ffffea60001db008
CPU: 0 UID: 0 PID: 2199114 Comm: tee Not tainted 6.14.0+ #4 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:split_huge_pmd_locked+0x3b5/0x2b60
Call Trace:
<TASK>
try_to_migrate_one+0x28c/0x3730
rmap_walk_anon+0x4f6/0x770
unmap_folio+0x196/0x1f0
split_huge_page_to_list_to_order+0x9f6/0x1560
deferred_split_scan+0xac5/0x12a0
shrinker_debugfs_scan_write+0x376/0x470
full_proxy_write+0x15c/0x220
vfs_write+0x2fc/0xcb0
ksys_write+0x146/0x250
do_syscall_64+0x6a/0x120
entry_SYSCALL_64_after_hwframe+0x76/0x7e

The bug is found by syzkaller on an internal kernel, then confirmed on
upstream.

Link: https://lkml.kernel.org/r/20250421113536.3682201-1-gavinguo@igalia.com
Link: https://lore.kernel.org/all/20250414072737.1698513-1-gavinguo@igalia.com/
Link: https://lore.kernel.org/all/20250418085802.2973519-1-gavinguo@igalia.com/
Fixes: 84c3fc4e9c ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Gavin Guo <gavinguo@igalia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Cc: Florent Revest <revest@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[gavin: backport the migration checking logic to __split_huge_pmd]
Signed-off-by: Gavin Guo <gavinguo@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-27 11:05:37 +01:00
..
damon mm/damon/vaddr: fix issue in damon_va_evenly_split_region() 2024-12-14 19:51:45 +01:00
kasan kasan: disable kasan_non_canonical_hook() for HW tags 2023-12-23 10:42:00 +01:00
kfence kfence: skip __GFP_THISNODE allocations on NUMA systems 2025-03-13 12:50:50 +01:00
backing-dev.c writeback, cgroup: fix null-ptr-deref write in bdi_split_work_to_wbs 2023-05-11 23:00:18 +09:00
balloon_compaction.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
bootmem_info.c bootmem: remove the vmemmap pages from kmemleak in put_page_bootmem 2022-08-31 17:16:48 +02:00
cleancache.c
cma_debug.c mm/cma: change cma mutex to irq safe spinlock 2021-05-05 11:27:21 -07:00
cma_sysfs.c mm: cma: support sysfs 2021-05-05 11:27:24 -07:00
cma.c mm/cma: drop incorrect alignment check in cma_init_reserved_mem 2024-07-05 09:14:13 +02:00
cma.h mm: cma: support sysfs 2021-05-05 11:27:24 -07:00
compaction.c mm, vmscan: prevent infinite loop for costly GFP_NOIO | __GFP_RETRY_MAYFAIL allocations 2024-04-10 16:19:37 +02:00
debug_page_ref.c
debug_vm_pgtable.c mm/debug_vm_pgtable: remove pte entry from the page table 2022-02-08 18:34:05 +01:00
debug.c mm/debug: sync up latest migrate_reason to migrate_reason_names 2021-09-24 16:13:35 -07:00
dmapool.c mm/dmapool: use DEVICE_ATTR_RO macro 2021-06-29 10:53:52 -07:00
early_ioremap.c mm/early_ioremap.c: remove redundant early_ioremap_shutdown() 2021-09-08 11:50:24 -07:00
fadvise.c
failslab.c
filemap.c filemap: Fix bounds checking in filemap_read() 2025-05-02 07:44:18 +02:00
frontswap.c mm/mempool: minor coding style tweaks 2021-05-05 11:27:27 -07:00
gup_test.c selftests/vm: gup_test: test faulting in kernel, and verify pinnable pages 2021-05-05 11:27:26 -07:00
gup_test.h selftests/vm: gup_test: fix test flag 2021-05-05 11:27:26 -07:00
gup.c mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() 2025-05-02 07:44:13 +02:00
highmem.c highmem: fix checks in __kmap_local_sched_{in,out} 2022-04-13 20:59:21 +02:00
hmm.c mm/hmm: fault non-owner device private entries 2022-08-03 12:03:54 +02:00
huge_memory.c mm/huge_memory: fix dereferencing invalid pmd migration entry 2025-06-27 11:05:37 +01:00
hugetlb_cgroup.c hugetlb: make free_huge_page irq safe 2021-05-05 11:27:22 -07:00
hugetlb_vmemmap.c mm: hugetlb: introduce CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON 2021-06-30 20:47:26 -07:00
hugetlb_vmemmap.h mm: hugetlb: introduce nr_free_vmemmap_pages in the struct hstate 2021-06-30 20:47:25 -07:00
hugetlb.c mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race 2025-06-27 11:05:35 +01:00
hwpoison-inject.c mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler 2022-07-12 16:35:05 +02:00
init-mm.c mm: add setup_initial_init_mm() helper 2021-07-08 11:48:21 -07:00
internal.h mm: unconditionally close VMAs on error 2024-12-14 19:50:38 +01:00
interval_tree.c mm/interval_tree: add comments to improve code readability 2021-04-30 11:20:38 -07:00
io-mapping.c mm: add a io_mapping_map_user helper 2021-04-30 11:20:39 -07:00
ioremap.c mm: move ioremap_page_range to vmalloc.c 2021-09-08 11:50:24 -07:00
Kconfig kmap_local: don't assume kmap PTEs are linear arrays in memory 2021-11-25 09:48:43 +01:00
Kconfig.debug mm, page_poison: remove CONFIG_PAGE_POISONING_ZERO 2020-12-15 12:13:46 -08:00
khugepaged.c mm/khugepaged: check again on anon uffd-wp during isolation 2023-04-26 13:51:52 +02:00
kmemleak.c Revert "mm: kmemleak: take a full lowmem check in kmemleak_*_phys()" 2022-09-15 11:30:00 +02:00
ksm.c mm/ksm: remove old GCC 4.9+ check 2021-09-13 10:18:28 -07:00
list_lru.c mm: vmscan: consolidate shrinker_maps handling code 2021-05-05 11:27:23 -07:00
maccess.c maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault() 2022-11-26 09:24:47 +01:00
madvise.c mm: fix madivse_pageout mishandling on non-LRU page 2022-10-05 10:39:39 +02:00
Makefile mm: introduce Data Access MONitor (DAMON) 2021-09-08 11:50:24 -07:00
mapping_dirty_helpers.c mm/mapping_dirty_helpers: remove double Note in kerneldoc 2021-07-01 11:06:02 -07:00
memblock.c memblock: allow to specify flags with memblock_add_node() 2023-12-20 15:17:33 +01:00
memcontrol.c memcg: always call cond_resched() after fn() 2025-06-04 14:38:06 +02:00
memfd.c memfd: check for non-NULL file_seals in memfd_create() syscall 2023-06-28 10:29:45 +02:00
memory_hotplug.c memblock: allow to specify flags with memblock_add_node() 2023-12-20 15:17:33 +01:00
memory-failure.c mm/hwpoison: do not send SIGBUS to processes with recovered clean pages 2025-05-02 07:44:04 +02:00
memory.c mm: fix apply_to_existing_page_range() 2025-05-02 07:44:24 +02:00
mempolicy.c mm/numa_balancing: teach mpol_to_str about the balancing mode 2024-08-19 05:45:17 +02:00
mempool.c kasan: use separate (un)poison implementation for integrated init 2021-06-04 19:32:21 +01:00
memremap.c mm/memremap.c: map FS_DAX device memory as decrypted 2022-11-16 09:58:27 +01:00
memtest.c memtest: use {READ,WRITE}_ONCE in memory scanning 2024-04-10 16:18:42 +02:00
migrate.c mm/migrate: set swap entry values of THP tail pages properly. 2024-04-10 16:19:31 +02:00
mincore.c inode: make init and permission helpers idmapped mount aware 2021-01-24 14:27:16 +01:00
mlock.c mm/mlock: fix potential imbalanced rlimit ucounts adjustment 2022-05-15 20:18:53 +02:00
mm_init.c include/linux/page-flags-layout.h: cleanups 2021-04-30 11:20:42 -07:00
mmap_lock.c mm: mmap_lock: replace get_memcg_path_buf() with on-stack buffer 2024-08-19 05:45:10 +02:00
mmap.c mm/hugetlb: unshare page tables during VMA split, not before 2025-06-27 11:05:35 +01:00
mmu_gather.c mm/khugepaged: fix GUP-fast interaction by sending IPI 2022-12-14 11:37:17 +01:00
mmu_notifier.c mm/mmu_notifier.c: fix race in mmu_interval_notifier_remove() 2022-04-27 14:38:58 +02:00
mmzone.c mm/lru: replace pgdat lru_lock with lruvec lock 2020-12-15 14:48:04 -08:00
mprotect.c mm: don't try to NUMA-migrate COW pages that have other uses 2022-02-23 12:03:03 +01:00
mremap.c mmmremap.c: avoid pointless invalidate_range_start/end on mremap(old_size=0) 2022-04-13 20:59:22 +02:00
msync.c mm/msync: exit early when the flags is an MS_ASYNC and start < vm_start 2021-04-30 11:20:37 -07:00
nommu.c mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling 2024-12-14 19:50:38 +01:00
oom_kill.c memcg: fix soft lockup in the OOM process 2025-03-13 12:50:48 +01:00
page_alloc.c mm/page_alloc.c: avoid infinite retries caused by cpuset race 2025-06-04 14:38:06 +02:00
page_counter.c mm: page_counter: mitigate consequences of a page_counter underflow 2021-04-30 11:20:38 -07:00
page_ext.c mm/migrate: add CPU hotplug to demotion #ifdef 2021-10-18 20:22:02 -10:00
page_idle.c mm/idle_page_tracking: make PG_idle reusable 2021-09-08 11:50:24 -07:00
page_io.c mm: fix unexpected zeroed page mapping with zram swap 2022-04-20 09:34:18 +02:00
page_isolation.c Merge branch 'akpm' (patches from Andrew) 2021-09-08 12:55:35 -07:00
page_owner.c mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE 2021-09-08 11:50:22 -07:00
page_poison.c mm: page_poison: print page info when corruption is caught 2021-04-30 11:20:36 -07:00
page_reporting.c mm/page_reporting: allow driver to specify reporting order 2021-06-29 10:53:47 -07:00
page_reporting.h mm/page_reporting: export reporting order as module parameter 2021-06-29 10:53:47 -07:00
page_vma_mapped.c mm: device exclusive memory access 2021-07-01 11:06:03 -07:00
page-writeback.c mm: fix ratelimit_pages update error in dirty_ratio_handler() 2025-06-27 11:05:26 +01:00
pagewalk.c mm: pagewalk: Fix race between unmap and page walker 2022-09-08 12:28:05 +02:00
percpu-internal.h Merge branch 'for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu 2021-07-01 17:17:24 -07:00
percpu-km.c percpu: flush tlb in pcpu_reclaim_populated() 2021-07-04 18:30:17 +00:00
percpu-stats.c percpu: rework memcg accounting 2021-06-05 20:43:15 +00:00
percpu-vm.c percpu: flush tlb in pcpu_reclaim_populated() 2021-07-04 18:30:17 +00:00
percpu.c memblock: drop memblock_free_early_nid() and memblock_free_early() 2025-03-13 12:50:07 +01:00
pgalloc-track.h mm: fix typos in comments 2021-05-07 00:26:35 -07:00
pgtable-generic.c mm/thp: fix __split_huge_pmd_locked() on shmem migration entry 2021-06-16 09:24:42 -07:00
process_vm_access.c mm/process_vm_access.c: remove duplicate include 2021-05-05 11:27:27 -07:00
ptdump.c mm: pagewalk: Fix race between unmap and page walker 2022-09-08 12:28:05 +02:00
readahead.c vfs: fix readahead(2) on block devices 2023-11-20 11:08:13 +01:00
rmap.c mm/rmap: Fix anon_vma->degree ambiguity leading to double-reuse 2022-09-05 10:30:07 +02:00
rodata_test.c
secretmem.c secretmem: disable memfd_secret() if arch cannot set direct map 2024-10-22 15:40:41 +02:00
shmem.c mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling 2024-12-14 19:50:38 +01:00
shuffle.c mm: eliminate "expecting prototype" kernel-doc warnings 2021-04-16 16:10:36 -07:00
shuffle.h mm/shuffle: fix section mismatch warning 2021-05-22 15:09:07 -10:00
slab_common.c mm, slab: remove duplicate kernel-doc comment for ksize() 2025-04-10 14:32:06 +02:00
slab.c slab: Introduce kmalloc_size_roundup() 2025-04-10 14:31:49 +02:00
slab.h mm, kfence: support kmem_dump_obj() for KFENCE objects 2022-04-27 14:38:51 +02:00
slob.c slab: Introduce kmalloc_size_roundup() 2025-04-10 14:31:49 +02:00
slub.c mm: slub: fix flush_cpu_slab()/__free_slab() invocations in task context. 2022-09-28 11:11:44 +02:00
sparse-vmemmap.c mm: sparsemem: split the huge PMD mapping of vmemmap pages 2021-06-30 20:47:26 -07:00
sparse.c memblock: drop memblock_free_early_nid() and memblock_free_early() 2025-03-13 12:50:07 +01:00
swap_cgroup.c
swap_slots.c mm: Replace deprecated CPU-hotplug functions. 2021-08-28 01:46:17 +02:00
swap_state.c mm: swap: get rid of livelock in swapin readahead 2022-03-23 09:16:41 +01:00
swap.c mm: fs: invalidate bh_lrus for only cold path 2021-09-24 16:13:35 -07:00
swapfile.c mm/swapfile: skip HugeTLB pages for unuse_vma 2024-10-22 15:40:41 +02:00
truncate.c Merge branch 'akpm' (patches from Andrew) 2021-09-03 10:08:28 -07:00
usercopy.c mm/usercopy: return 1 from hardened_usercopy __setup() handler 2022-04-08 14:24:14 +02:00
userfaultfd.c userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb 2024-03-01 13:21:43 +01:00
util.c mm: unconditionally close VMAs on error 2024-12-14 19:50:38 +01:00
vmacache.c
vmalloc.c mm: don't skip arch_sync_kernel_mappings() in error paths 2025-03-13 12:51:03 +01:00
vmpressure.c net-memcg: Fix scope of sockmem pressure indicators 2023-09-19 12:22:33 +02:00
vmscan.c mm: add missing release barrier on PGDAT_RECLAIM_LOCKED unlock 2025-05-02 07:44:04 +02:00
vmstat.c vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event 2024-12-14 19:50:33 +01:00
workingset.c memcg: sync flush only if periodic flush is delayed 2022-04-27 14:38:57 +02:00
z3fold.c mm/z3fold: add kerneldoc fields for z3fold_pool 2021-07-01 11:06:03 -07:00
zbud.c mm/zbud: add kerneldoc fields for zbud_pool 2021-07-01 11:06:03 -07:00
zpool.c mm: fix typos in comments 2021-05-07 00:26:35 -07:00
zsmalloc.c zsmalloc: fix races between asynchronous zspage free and page migration 2022-06-06 08:43:39 +02:00
zswap.c mm/zswap.c: fix two bugs in zswap_writeback_entry() 2021-06-30 20:47:31 -07:00