[moderation] [mm?] KCSAN: data-race in __filemap_remove_folio / nr_blockdev_pages (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5939d45155bb Merge tag 'trace-v6.9-rc3' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15fd1547180000
kernel config: https://syzkaller.appspot.com/x/.config?x=6a1ac6d65bf295c5
dashboard link: https://syzkaller.appspot.com/bug?extid=df8f5982632041cfba26
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/de269661ae3f/disk-5939d451.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f5a7a2ebfc8c/vmlinux-5939d451.xz
kernel image: https://storage.googleapis.com/syzbot-assets/33b7271c393c/bzImage-5939d451.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+df8f59...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __filemap_remove_folio / nr_blockdev_pages

read-write to 0xffff8881004c11f8 of 8 bytes by task 21186 on cpu 1:
page_cache_delete mm/filemap.c:154 [inline]
__filemap_remove_folio+0x1c5/0x2c0 mm/filemap.c:232
__remove_mapping+0x341/0x470 mm/vmscan.c:762
remove_mapping+0x22/0x90 mm/vmscan.c:795
mapping_evict_folio mm/truncate.c:293 [inline]
mapping_try_invalidate+0x288/0x3e0 mm/truncate.c:511
invalidate_mapping_pages+0x27/0x40 mm/truncate.c:549
invalidate_bdev+0x65/0x80 block/bdev.c:96
ext4_put_super+0x51b/0x7e0 fs/ext4/super.c:1361
generic_shutdown_super+0xde/0x210 fs/super.c:641
kill_block_super+0x2a/0x70 fs/super.c:1675
ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7327
deactivate_locked_super+0x7d/0x1c0 fs/super.c:472
deactivate_super+0x9f/0xb0 fs/super.c:505
cleanup_mnt+0x272/0x2e0 fs/namespace.c:1267
__cleanup_mnt+0x19/0x20 fs/namespace.c:1274
task_work_run+0x13a/0x1a0 kernel/task_work.c:180
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+0xda/0x1d0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881004c11f8 of 8 bytes by task 3155 on cpu 0:
nr_blockdev_pages+0x7c/0xd0 block/bdev.c:455
si_meminfo+0x87/0xd0 mm/show_mem.c:80
update_defense_level+0x46/0x610 net/netfilter/ipvs/ip_vs_ctl.c:101
defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
worker_thread+0x526/0x730 kernel/workqueue.c:3416
kthread+0x1d1/0x210 kernel/kthread.c:388
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x0000000000000007 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3155 Comm: kworker/0:2 Tainted: G W 6.9.0-rc3-syzkaller-00286-g5939d45155bb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events_long defense_work_handler
==================================================================
bridge0: port 1(bridge_slave_0) entered blocking state
bridge0: port 1(bridge_slave_0) entered forwarding state


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