syzbot


KCSAN: data-race in p9_conn_cancel / p9_poll_workfn (4)

Status: moderation: reported on 2024/03/28 19:52
Subsystems: v9fs
[Documentation on labels]
Reported-by: syzbot+a789bed6117496300826@syzkaller.appspotmail.com
First crash: 23d, last: 23d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in p9_conn_cancel / p9_poll_workfn (2) v9fs 1 271d 271d 0/26 auto-obsoleted due to no activity on 2023/08/28 09:43
upstream KCSAN: data-race in p9_conn_cancel / p9_poll_workfn (3) v9fs 1 213d 213d 0/26 auto-obsoleted due to no activity on 2023/10/26 00:39
upstream KCSAN: data-race in p9_conn_cancel / p9_poll_workfn v9fs 1 967d 967d 0/26 auto-closed as invalid on 2021/10/01 19:17

Sample crash report:
==================================================================
BUG: KCSAN: data-race in p9_conn_cancel / p9_poll_workfn

write to 0xffff88813c87ec28 of 4 bytes by task 10042 on cpu 1:
 p9_conn_cancel+0x89/0x400 net/9p/trans_fd.c:200
 p9_read_work+0x771/0x8d0 net/9p/trans_fd.c:407
 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 0xffff88813c87ec28 of 4 bytes by task 3171 on cpu 0:
 p9_poll_mux net/9p/trans_fd.c:626 [inline]
 p9_poll_workfn+0xc0/0x420 net/9p/trans_fd.c:1178
 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 -> 0xfffffffb

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3171 Comm: kworker/0:4 Not tainted 6.9.0-rc1-syzkaller-00061-g8d025e2092e2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events p9_poll_workfn
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/28 19:52 upstream 8d025e2092e2 e91187ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in p9_conn_cancel / p9_poll_workfn
* Struck through repros no longer work on HEAD.