[moderation] [v9fs?] KCSAN: data-race in p9_conn_cancel / p9_poll_workfn (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9f16d5e6f220 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1568775f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=3d7fd5be0e73b8b
dashboard link: https://syzkaller.appspot.com/bug?extid=d364aa9986167a4b48ce
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [asma...@codewreck.org eri...@kernel.org linux-...@vger.kernel.org linu...@crudebyte.com lu...@ionkov.net v9...@lists.linux.dev]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9fa7a64f26d5/disk-9f16d5e6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/800b086e8afd/vmlinux-9f16d5e6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/21f5373315cb/bzImage-9f16d5e6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d364aa...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in p9_conn_cancel / p9_poll_workfn

write to 0xffff888118619628 of 4 bytes by task 10914 on cpu 0:
p9_conn_cancel+0x89/0x400 net/9p/trans_fd.c:199
p9_read_work+0x765/0x8c0 net/9p/trans_fd.c:406
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

read to 0xffff888118619628 of 4 bytes by task 4633 on cpu 1:
p9_poll_mux net/9p/trans_fd.c:625 [inline]
p9_poll_workfn+0xc0/0x410 net/9p/trans_fd.c:1177
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: 0x00000000 -> 0xfffffffb

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4633 Comm: kworker/1:5 Not tainted 6.12.0-syzkaller-09073-g9f16d5e6f220 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events p9_poll_workfn
==================================================================


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[syzbot]

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