[moderation] [v9fs?] KCSAN: data-race in p9_conn_cancel / p9_poll_workfn (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6ba59ff42279 Linux 6.10-rc4
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17f8cca6980000
kernel config: https://syzkaller.appspot.com/x/.config?x=6506c0d5147633de
dashboard link: https://syzkaller.appspot.com/bug?extid=b4d211ced36373fe2b84
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/188d33134c3f/disk-6ba59ff4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2fd18f514342/vmlinux-6ba59ff4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d0e205f1f56d/bzImage-6ba59ff4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b4d211...@syzkaller.appspotmail.com

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

write to 0xffff888116978028 of 4 bytes by task 3178 on cpu 0:
p9_conn_cancel+0x89/0x400 net/9p/trans_fd.c:199
p9_write_work+0x3ac/0x750 net/9p/trans_fd.c:522
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
worker_thread+0x526/0x730 kernel/workqueue.c:3393
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 0xffff888116978028 of 4 bytes by task 7207 on cpu 1:
p9_poll_mux net/9p/trans_fd.c:625 [inline]
p9_poll_workfn+0xc0/0x420 net/9p/trans_fd.c:1177
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
worker_thread+0x526/0x730 kernel/workqueue.c:3393
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 -> 0xffffff8f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7207 Comm: kworker/1:12 Tainted: G W 6.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: events p9_poll_workfn
==================================================================


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