KCSAN: data-race in __blk_mq_sched_dispatch_requests / __blk_mq_sched_dispatch

KCSAN: data-race in __blk_mq_sched_dispatch_requests / __blk_mq_sched_dispatch_requests (3)
Status: moderation: reported on 2020/12/07 11:13
Reported-by: syzbot+7f254b31c6a813e862cc@syzkaller.appspotmail.com
First crash: 59d, last: 13d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __blk_mq_sched_dispatch_requests / __blk_mq_sched_dispatch_requests				3	147d	178d	0/17	auto-closed as invalid on 2020/10/05 06:08
upstream	KCSAN: data-race in __blk_mq_sched_dispatch_requests / __blk_mq_sched_dispatch_requests (2)				3	98d	106d	0/17	auto-closed as invalid on 2020/11/22 21:54

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __blk_mq_sched_dispatch_requests / __blk_mq_sched_dispatch_requests

write to 0xffff888101029810 of 8 bytes by task 2048 on cpu 1:
 INIT_LIST_HEAD include/linux/list.h:36 [inline]
 list_splice_init include/linux/list.h:483 [inline]
 __blk_mq_sched_dispatch_requests+0x16a/0x2a0 block/blk-mq-sched.c:289
 blk_mq_sched_dispatch_requests+0x8f/0xf0 block/blk-mq-sched.c:341
 __blk_mq_run_hw_queue block/blk-mq.c:1515 [inline]
 __blk_mq_delay_run_hw_queue+0x1ff/0x410 block/blk-mq.c:1592
 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1645
 blk_mq_run_hw_queues block/blk-mq.c:1663 [inline]
 blk_mq_requeue_work+0x423/0x490 block/blk-mq.c:824
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x635/0xb90 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff888101029810 of 8 bytes by task 2198 on cpu 0:
 list_empty_careful include/linux/list.h:319 [inline]
 __blk_mq_sched_dispatch_requests+0xb1/0x2a0 block/blk-mq-sched.c:286
 blk_mq_sched_dispatch_requests+0x8f/0xf0 block/blk-mq-sched.c:341
 __blk_mq_run_hw_queue block/blk-mq.c:1515 [inline]
 blk_mq_run_work_fn+0xb3/0x130 block/blk-mq.c:1793
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x635/0xb90 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2198 Comm: kworker/0:1H Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kblockd blk_mq_run_work_fn
==================================================================

Crashes (5):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci2-upstream-kcsan-gce	2021/01/12 01:30	upstream	a0d54b4f	2c1f2513	.config	log	report	info	axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/12/20 09:18	upstream	467f8165	04201c06	.config	log	report	info	axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/12/18 01:55	upstream	d64c6f96	04201c06	.config	log	report	info	axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/12/07 10:06	upstream	0477e928	f80ce148	.config	log	report	info	axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/11/26 19:35	upstream	4df91062	2f1cec62	.config	log	report	info	axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org