[moderation] [fs?] KCSAN: data-race in page_cache_sync_ra / read_pages (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 09a0fa92e5b4 Merge tag 'selinux-pr-20250107' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14de4ef8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9ab3e6c069ff12aa
dashboard link: https://syzkaller.appspot.com/bug?extid=96dc7bc0a64256a37e22
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/75587a910ad9/disk-09a0fa92.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d163b2a3956e/vmlinux-09a0fa92.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e11b5d202937/bzImage-09a0fa92.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+96dc7b...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in page_cache_sync_ra / read_pages

write to 0xffff88811c4393a4 of 4 bytes by task 5358 on cpu 1:
page_cache_sync_ra+0x540/0x670
page_cache_sync_readahead include/linux/pagemap.h:1397 [inline]
filemap_get_pages+0x2c1/0x10e0 mm/filemap.c:2537
filemap_read+0x221/0x6a0 mm/filemap.c:2637
generic_file_read_iter+0x78/0x330 mm/filemap.c:2825
ext4_file_read_iter+0x1cc/0x290
copy_splice_read+0x3a0/0x5d0 fs/splice.c:365
do_splice_read fs/splice.c:984 [inline]
splice_direct_to_actor+0x28b/0x670 fs/splice.c:1089
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x398/0x660 fs/read_write.c:1363
__do_sys_sendfile64 fs/read_write.c:1424 [inline]
__se_sys_sendfile64 fs/read_write.c:1410 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
x64_sys_call+0xfbd/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:41
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

read to 0xffff88811c4393a4 of 4 bytes by task 5363 on cpu 0:
read_pages+0x25c/0x540 mm/readahead.c:171
page_cache_ra_unbounded+0x2b8/0x310 mm/readahead.c:295
page_cache_sync_ra+0x652/0x670
page_cache_sync_readahead include/linux/pagemap.h:1397 [inline]
filemap_get_pages+0x2c1/0x10e0 mm/filemap.c:2537
filemap_read+0x221/0x6a0 mm/filemap.c:2637
generic_file_read_iter+0x78/0x330 mm/filemap.c:2825
ext4_file_read_iter+0x1cc/0x290
copy_splice_read+0x3a0/0x5d0 fs/splice.c:365
do_splice_read fs/splice.c:984 [inline]
splice_direct_to_actor+0x28b/0x670 fs/splice.c:1089
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x398/0x660 fs/read_write.c:1363
__do_sys_sendfile64 fs/read_write.c:1424 [inline]
__se_sys_sendfile64 fs/read_write.c:1410 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
x64_sys_call+0xfbd/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:41
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: 0x00000002 -> 0x00000010

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5363 Comm: syz.2.543 Not tainted 6.13.0-rc6-syzkaller-00038-g09a0fa92e5b4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.