syzbot

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BUG: KCSAN: data-race in p9_conn_cancel / p9_read_work

write to 0xffff8881267b9e28 of 4 bytes by task 3173 on cpu 0:
 p9_conn_cancel+0x89/0x400 net/9p/trans_fd.c:200
 p9_write_work+0x3ac/0x750 net/9p/trans_fd.c:523
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

read to 0xffff8881267b9e28 of 4 bytes by task 5724 on cpu 1:
 p9_read_work+0x34/0x8d0 net/9p/trans_fd.c:287
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

value changed: 0x00000000 -> 0xffffff91

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5724 Comm: kworker/1:7 Tainted: G        W          6.8.0-syzkaller-11339-g741e9d668aa5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: events p9_read_work
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