KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_do_dispatch

KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_do_dispatch_sched
Status: auto-closed as invalid on 2020/07/30 00:43
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 463d, last: 458d

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_do_dispatch_sched (2)				8	351d	421d	0/22	auto-closed as invalid on 2020/11/14 12:11
upstream	KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_do_dispatch_sched (3)				28	117d	293d	0/22	auto-closed as invalid on 2021/07/05 21:10

Sample crash report:

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

write to 0xffff888129633810 of 8 bytes by task 3222 on cpu 1:
 INIT_LIST_HEAD include/linux/list.h:36 [inline]
 list_splice_init include/linux/list.h:465 [inline]
 __blk_mq_sched_dispatch_requests+0x179/0x2a0 block/blk-mq-sched.c:224
 blk_mq_sched_dispatch_requests+0x7c/0xe0 block/blk-mq-sched.c:276
 __blk_mq_run_hw_queue+0xee/0x1c0 block/blk-mq.c:1418
 __blk_mq_delay_run_hw_queue+0x188/0x330 block/blk-mq.c:1495
 blk_mq_run_hw_queue+0x21c/0x240 block/blk-mq.c:1548
 blk_mq_run_hw_queues block/blk-mq.c:1566 [inline]
 blk_mq_requeue_work+0x43f/0x490 block/blk-mq.c:774
 process_one_work+0x3cb/0x990 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x210/0x220 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

read to 0xffff888129633810 of 8 bytes by task 3221 on cpu 0:
 list_empty_careful include/linux/list.h:301 [inline]
 blk_mq_do_dispatch_sched+0xe4/0x2b0 block/blk-mq-sched.c:106
 __blk_mq_sched_dispatch_requests+0x1ff/0x2a0 block/blk-mq-sched.c:245
 blk_mq_sched_dispatch_requests+0x7c/0xe0 block/blk-mq-sched.c:276
 __blk_mq_run_hw_queue+0xee/0x1c0 block/blk-mq.c:1418
 blk_mq_run_work_fn+0x30/0x40 block/blk-mq.c:1696
 process_one_work+0x3cb/0x990 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x210/0x220 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3221 Comm: kworker/0:1H Not tainted 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kblockd blk_mq_run_work_fn
==================================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2020/06/25 00:39	upstream	26e122e97a3d	9d60b18e	.config	log	report
ci2-upstream-kcsan-gce	2020/06/19 21:22	upstream	672f9255a727	123cf502	.config	log	report