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KCSAN: data-race in p9_conn_cancel / p9_write_work (7)

Status: upstream: reported on 2025/02/11 20:11
Subsystems: v9fs
[Documentation on labels]
Reported-by: syzbot+d69a7cc8c683c2cb7506@syzkaller.appspotmail.com
First crash: 9d10h, last: 9d10h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [v9fs?] KCSAN: data-race in p9_conn_cancel / p9_write_work (7) 0 (1) 2025/02/11 20:11
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in p9_conn_cancel / p9_write_work (5) v9fs 3 279d 319d 0/28 auto-obsoleted due to no activity on 2024/06/21 12:43
upstream KCSAN: data-race in p9_conn_cancel / p9_write_work (4) v9fs 2 450d 474d 0/28 auto-obsoleted due to no activity on 2024/01/02 07:46
upstream KCSAN: data-race in p9_conn_cancel / p9_write_work (6) v9fs 4 139d 212d 0/28 auto-obsoleted due to no activity on 2024/11/08 10:55
upstream KCSAN: data-race in p9_conn_cancel / p9_write_work v9fs 1 1548d 1532d 0/28 auto-closed as invalid on 2020/12/30 07:04
upstream KCSAN: data-race in p9_conn_cancel / p9_write_work (3) v9fs 1 1038d 1038d 0/28 auto-closed as invalid on 2022/05/24 19:24
upstream KCSAN: data-race in p9_conn_cancel / p9_write_work (2) v9fs 2 1480d 1492d 0/28 auto-closed as invalid on 2021/03/08 14:39

Sample crash report:
==================================================================
BUG: KCSAN: data-race in p9_conn_cancel / p9_write_work

write to 0xffff88810db66428 of 4 bytes by task 23357 on cpu 1:
 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:3236 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3317
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3398
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff88810db66428 of 4 bytes by task 23378 on cpu 0:
 p9_write_work+0x26/0x750 net/9p/trans_fd.c:453
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3317
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3398
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00000000 -> 0xffffff98

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 23378 Comm: kworker/0:8 Tainted: G        W          6.14.0-rc2-syzkaller-00034-gfebbc555cf0f #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: events p9_write_work
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/11 18:38 upstream febbc555cf0f f2baddf5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in p9_conn_cancel / p9_write_work
* Struck through repros no longer work on HEAD.