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8001070cfb
I found a report from syzbot [1]
This report shows that the value can be changed, but in reality, the
value of __folio_set_movable() cannot be changed because it holds the
folio refcount.
Therefore, it is appropriate to add an annotate to make KCSAN
ignore that data-race.
[1]
==================================================================
BUG: KCSAN: data-race in __filemap_remove_folio / migrate_pages_batch
write to 0xffffea0004b81dd8 of 8 bytes by task 6348 on cpu 0:
page_cache_delete mm/filemap.c:153 [inline]
__filemap_remove_folio+0x1ac/0x2c0 mm/filemap.c:233
filemap_remove_folio+0x6b/0x1f0 mm/filemap.c:265
truncate_inode_folio+0x42/0x50 mm/truncate.c:178
shmem_undo_range+0x25b/0xa70 mm/shmem.c:1028
shmem_truncate_range mm/shmem.c:1144 [inline]
shmem_evict_inode+0x14d/0x530 mm/shmem.c:1272
evict+0x2f0/0x580 fs/inode.c:731
iput_final fs/inode.c:1883 [inline]
iput+0x42a/0x5b0 fs/inode.c:1909
dentry_unlink_inode+0x24f/0x260 fs/dcache.c:412
__dentry_kill+0x18b/0x4c0 fs/dcache.c:615
dput+0x5c/0xd0 fs/dcache.c:857
__fput+0x3fb/0x6d0 fs/file_table.c:439
____fput+0x1c/0x30 fs/file_table.c:459
task_work_run+0x13a/0x1a0 kernel/task_work.c:228
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0xbe/0x130 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
read to 0xffffea0004b81dd8 of 8 bytes by task 6342 on cpu 1:
__folio_test_movable include/linux/page-flags.h:699 [inline]
migrate_folio_unmap mm/migrate.c:1199 [inline]
migrate_pages_batch+0x24c/0x1940 mm/migrate.c:1797
migrate_pages_sync mm/migrate.c:1963 [inline]
migrate_pages+0xff1/0x1820 mm/migrate.c:2072
do_mbind mm/mempolicy.c:1390 [inline]
kernel_mbind mm/mempolicy.c:1533 [inline]
__do_sys_mbind mm/mempolicy.c:1607 [inline]
__se_sys_mbind+0xf76/0x1160 mm/mempolicy.c:1603
__x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1603
x64_sys_call+0x2b4d/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:238
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
value changed: 0xffff888127601078 -> 0x0000000000000000
Link: https://lkml.kernel.org/r/20240924130053.107490-1-aha310510@gmail.com
Fixes: 7e2a5e5ab2 ("mm: migrate: use __folio_test_movable()")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.