[moderation] [block?] KCSAN: data-race in delete_from_page_cache_batch / nr_blockdev_pages (12)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9e4c6c1ad9a1 Merge tag 'io_uring-6.12-20241011' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14273b27980000
kernel config: https://syzkaller.appspot.com/x/.config?x=a2f7ae2f221e9eae
dashboard link: https://syzkaller.appspot.com/bug?extid=88fd57beeb6a7d1489de
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ax...@kernel.dk linux...@vger.kernel.org linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d3779bcdcbb2/disk-9e4c6c1a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f46317f8fff8/vmlinux-9e4c6c1a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e82f600d6456/bzImage-9e4c6c1a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+88fd57...@syzkaller.appspotmail.com

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

read-write to 0xffff8881004c1830 of 8 bytes by task 9169 on cpu 0:
page_cache_delete_batch mm/filemap.c:325 [inline]
delete_from_page_cache_batch+0x4f3/0x700 mm/filemap.c:344
truncate_inode_pages_range+0x1c5/0x6b0 mm/truncate.c:343
truncate_inode_pages+0x24/0x30 mm/truncate.c:423
kill_bdev block/bdev.c:91 [inline]
blkdev_flush_mapping+0xa5/0x1a0 block/bdev.c:671
blkdev_put_whole block/bdev.c:678 [inline]
bdev_release+0x2f9/0x420 block/bdev.c:1103
blkdev_release+0x15/0x20 block/fops.c:639
__fput+0x17a/0x6d0 fs/file_table.c:431
__fput_sync+0x43/0x60 fs/file_table.c:516
__do_sys_close fs/open.c:1565 [inline]
__se_sys_close+0xf9/0x1a0 fs/open.c:1550
__x64_sys_close+0x1f/0x30 fs/open.c:1550
x64_sys_call+0x25cb/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:4
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 0xffff8881004c1830 of 8 bytes by task 3335 on cpu 1:
nr_blockdev_pages+0x7c/0xd0 block/bdev.c:482
si_meminfo+0x87/0xd0 mm/show_mem.c:80
update_defense_level+0x49/0x5b0 net/netfilter/ipvs/ip_vs_ctl.c:102
defense_work_handler+0x1f/0x80 net/netfilter/ipvs/ip_vs_ctl.c:235
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
kthread+0x1d1/0x210 kernel/kthread.c:389
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: 0x0000000000000009 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3335 Comm: kworker/1:2 Not tainted 6.12.0-rc2-syzkaller-00260-g9e4c6c1ad9a1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events_long defense_work_handler
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup