==================================================================
BUG: KCSAN: data-race in p9_poll_workfn / p9_write_work

write to 0xffff88812d8d5494 of 4 bytes by task 25 on cpu 1:
 p9_write_work+0x46f/0x780 net/9p/trans_fd.c:495
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

read to 0xffff88812d8d5494 of 4 bytes by task 1879 on cpu 0:
 p9_poll_mux net/9p/trans_fd.c:642 [inline]
 p9_poll_workfn+0x202/0x410 net/9p/trans_fd.c:1147
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x00000009 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1879 Comm: kworker/0:3 Not tainted 6.0.0-rc5-syzkaller-00017-gd1221cea11fc-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Workqueue: events p9_poll_workfn
==================================================================