KCSAN: data-race in create_io_worker / io_wqe_wake

KCSAN: data-race in create_io_worker / io_wqe_wake_worker
Status: auto-closed as invalid on 2020/11/14 12:51
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 355d, last: 345d

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in create_io_worker / io_wqe_wake_worker (4)	1	220d	220d	0/22	auto-closed as invalid on 2021/03/19 11:24
upstream	KCSAN: data-race in create_io_worker / io_wqe_wake_worker (2)	1	300d	287d	0/22	auto-closed as invalid on 2020/12/29 17:31
upstream	KCSAN: data-race in create_io_worker / io_wqe_wake_worker (3)	2	258d	264d	0/22	auto-closed as invalid on 2021/02/09 23:53

Sample crash report:

==================================================================
BUG: KCSAN: data-race in create_io_worker / io_wqe_wake_worker

write to 0xffff88808d610044 of 4 bytes by task 17886 on cpu 0:
 create_io_worker+0x2ad/0x320 fs/io-wq.c:667
 io_wq_manager+0x415/0x5c0 fs/io-wq.c:730
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff88808d610044 of 4 bytes by task 17884 on cpu 1:
 io_wqe_wake_worker+0x160/0x220 fs/io-wq.c:293
 io_wqe_enqueue+0x2b8/0x340 fs/io-wq.c:831
 io_wq_enqueue+0x3a/0x40 fs/io-wq.c:838
 __io_queue_async_work fs/io_uring.c:1198 [inline]
 io_queue_async_work+0x16b/0x3c0 fs/io_uring.c:1208
 __io_queue_sqe+0x4a3/0x670 fs/io_uring.c:6198
 io_queue_sqe+0x81/0x220 fs/io_uring.c:6261
 io_submit_sqe+0x333/0x550 fs/io_uring.c:6331
 io_submit_sqes+0x8c6/0xfb0 fs/io_uring.c:6525
 __do_sys_io_uring_enter fs/io_uring.c:8353 [inline]
 __se_sys_io_uring_enter+0x1e8/0x790 fs/io_uring.c:8312
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:8312
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17884 Comm: syz-executor.4 Not tainted 5.9.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2020/10/10 12:47	upstream	6f2f486d57c4	b74c49a6	.config	log	report			info
ci2-upstream-kcsan-gce	2020/09/30 08:38	upstream	02de58b24d2e	8516f6d3	.config	log	report			info