[moderation] [ext4?] KCSAN: data-race in __filemap_add_folio / nr_blockdev_pages (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f1a09972a45a Merge tag 'ata-6.7-rc3' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=122185c8e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8c1151391aefc0c3
dashboard link: https://syzkaller.appspot.com/bug?extid=a0bf2421e1edfc040964
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [adilger...@dilger.ca ak...@linux-foundation.org linux...@vger.kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@kvack.org ty...@mit.edu wi...@infradead.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dffb0d99ad2d/disk-f1a09972.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/080ad4a9580e/vmlinux-f1a09972.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f1ac25646188/bzImage-f1a09972.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a0bf24...@syzkaller.appspotmail.com

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

read-write to 0xffff8881006324b0 of 8 bytes by task 6050 on cpu 0:
__filemap_add_folio+0x4c1/0x730 mm/filemap.c:902
filemap_add_folio+0x70/0x160 mm/filemap.c:937
page_cache_ra_unbounded+0x15e/0x2e0 mm/readahead.c:250
do_page_cache_ra mm/readahead.c:299 [inline]
force_page_cache_ra mm/readahead.c:330 [inline]
page_cache_sync_ra+0x24b/0x2a0 mm/readahead.c:691
page_cache_sync_readahead include/linux/pagemap.h:1266 [inline]
filemap_get_pages+0x251/0xf90 mm/filemap.c:2497
filemap_read+0x214/0x680 mm/filemap.c:2593
blkdev_read_iter+0x217/0x2c0 block/fops.c:742
call_read_iter include/linux/fs.h:2014 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x3c0/0x590 fs/read_write.c:470
ksys_read+0xeb/0x1a0 fs/read_write.c:613
__do_sys_read fs/read_write.c:623 [inline]
__se_sys_read fs/read_write.c:621 [inline]
__x64_sys_read+0x42/0x50 fs/read_write.c:621
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881006324b0 of 8 bytes by task 3187 on cpu 1:
nr_blockdev_pages+0x7c/0xd0 block/bdev.c:441
si_meminfo+0x87/0xd0 mm/show_mem.c:80
update_defense_level+0x46/0x600 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:2630 [inline]
process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2703
worker_thread+0x525/0x730 kernel/workqueue.c:2784
kthread+0x1d7/0x210 kernel/kthread.c:388
ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

value changed: 0x0000000000000001 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3187 Comm: kworker/1:3 Not tainted 6.7.0-rc2-syzkaller-00147-gf1a09972a45a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
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