[moderation] [fs?] KCSAN: data-race in has_bh_in_lru / invalidate_bh_lrus_cpu (14)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3ba7dfb8da62 Merge tag 'rcu-next-v6.15' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16d34198580000
kernel config: https://syzkaller.appspot.com/x/.config?x=79f1cf4142160c34
dashboard link: https://syzkaller.appspot.com/bug?extid=fc5ae3d753e70fa9d8e0
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/dd40b872cca9/disk-3ba7dfb8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/86a3a241fb7d/vmlinux-3ba7dfb8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1ce46917915c/bzImage-3ba7dfb8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fc5ae3...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in has_bh_in_lru / invalidate_bh_lrus_cpu

write to 0xffff888237c2ba28 of 8 bytes by task 9 on cpu 0:
__invalidate_bh_lrus fs/buffer.c:1499 [inline]
invalidate_bh_lrus_cpu+0x85/0xc0 fs/buffer.c:1544
lru_add_and_bh_lrus_drain mm/swap.c:746 [inline]
lru_add_drain_per_cpu+0x62/0x80 mm/swap.c:765
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0x4db/0xa20 kernel/workqueue.c:3319
worker_thread+0x51d/0x6f0 kernel/workqueue.c:3400
kthread+0x4ae/0x520 kernel/kthread.c:464
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff888237c2ba28 of 8 bytes by task 13219 on cpu 1:
has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1521
smp_call_function_many_cond+0x305/0xbb0 kernel/smp.c:838
on_each_cpu_cond_mask+0x3c/0x90 kernel/smp.c:1052
on_each_cpu_cond include/linux/smp.h:105 [inline]
invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1530
kill_bdev block/bdev.c:90 [inline]
blkdev_flush_mapping+0x9b/0x1a0 block/bdev.c:674
blkdev_put_whole block/bdev.c:681 [inline]
bdev_release+0x2f9/0x420 block/bdev.c:1106
blkdev_release+0x15/0x20 block/fops.c:660
__fput+0x2ac/0x640 fs/file_table.c:465
____fput+0x1c/0x30 fs/file_table.c:493
task_work_run+0x13a/0x1a0 kernel/task_work.c:227
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:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff8881006fb208 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13219 Comm: syz-executor Not tainted 6.14.0-syzkaller-00685-g3ba7dfb8da62 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


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[syzbot]

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