syzbot

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BUG: KCSAN: data-race in p9_conn_cancel / p9_write_work

write to 0xffff888122b74428 of 4 bytes by task 3343 on cpu 0:
 p9_conn_cancel+0x89/0x400 net/9p/trans_fd.c:199
 p9_poll_mux net/9p/trans_fd.c:631 [inline]
 p9_poll_workfn+0x133/0x410 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

read to 0xffff888122b74428 of 4 bytes by task 24 on cpu 1:
 p9_write_work+0x26/0x750 net/9p/trans_fd.c:453
 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 -> 0xffffff98

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Tainted: G        W          6.12.0-rc1-syzkaller-00125-g0c559323bbaa #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events p9_write_work
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