syzbot


KCSAN: data-race in io_sq_thread / io_sq_thread_stop

Status: moderation: reported on 2024/12/22 20:43
Subsystems: io-uring
[Documentation on labels]
Reported-by: syzbot+5988142e8a69a67b1418@syzkaller.appspotmail.com
First crash: 57d, last: 8d03h
Discussions (1)
Title Replies (including bot) Last reply
[PATCH] io_uring/sqpoll: annotate data race for access in debug check 3 (3) 2025/01/08 16:42

Sample crash report:
==================================================================
BUG: KCSAN: data-race in io_sq_thread / io_sq_thread_stop

write to 0xffff88810c166e78 of 8 bytes by task 16288 on cpu 0:
 io_sq_thread+0xe98/0x1100 io_uring/sqpoll.c:382
 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 0xffff88810c166e78 of 8 bytes by task 142 on cpu 1:
 io_sq_thread_stop+0x1d/0xd0 io_uring/sqpoll.c:60
 io_put_sq_data io_uring/sqpoll.c:76 [inline]
 io_sq_thread_finish+0x252/0x2d0 io_uring/sqpoll.c:101
 io_ring_ctx_free+0x1a/0x3d0 io_uring/io_uring.c:2698
 io_ring_exit_work+0x4d9/0x510 io_uring/io_uring.c:2939
 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: 0xffff8881328fb180 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 142 Comm: kworker/u8:4 Not tainted 6.14.0-rc1-syzkaller-00276-g69b54314c975 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: iou_exit io_ring_exit_work
==================================================================
IPVS: Schedule: port zero only supported in persistent services, check your ipvs configuration

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/10 06:45 upstream 69b54314c975 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in io_sq_thread / io_sq_thread_stop
2025/01/04 05:12 upstream 63676eefb7a0 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in io_sq_thread / io_sq_thread_stop
2024/12/22 20:42 upstream bcde95ce32b6 b4fbdbd4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in io_sq_thread / io_sq_thread_stop
* Struck through repros no longer work on HEAD.