syzbot


KCSAN: data-race in __mod_timer / blk_add_timer (3)

Status: auto-closed as invalid on 2022/02/04 22:18
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 439d, last: 341d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __mod_timer / blk_add_timer 2 566d 600d 0/24 auto-closed as invalid on 2021/06/25 00:11
upstream KCSAN: data-race in __mod_timer / blk_add_timer (2) 2 491d 521d 0/24 auto-closed as invalid on 2021/09/07 18:24
upstream KCSAN: data-race in __mod_timer / blk_add_timer (4) 2 248d 267d 0/24 auto-closed as invalid on 2022/05/08 11:46
upstream KCSAN: data-race in __mod_timer / blk_add_timer (5) 1 104d 104d 0/24 auto-closed as invalid on 2022/09/29 13:43

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __mod_timer / blk_add_timer

write to 0xffff888101e93ac8 of 8 bytes by task 39 on cpu 1:
 __mod_timer+0x720/0xc30 kernel/time/timer.c:1052
 mod_timer+0x1b/0x20 kernel/time/timer.c:1108
 blk_mq_timeout_work+0xca/0x2b0 block/blk-mq.c:1276
 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
 worker_thread+0x616/0xa70 kernel/workqueue.c:2445
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

read to 0xffff888101e93ac8 of 8 bytes by task 237 on cpu 0:
 blk_add_timer+0x11f/0x1a0
 blk_mq_start_request+0xfe/0x290 block/blk-mq.c:1049
 loop_queue_rq+0x42/0x5b0 drivers/block/loop.c:1804
 blk_mq_dispatch_rq_list+0x534/0x11e0 block/blk-mq.c:1663
 __blk_mq_sched_dispatch_requests+0x23b/0x270 block/blk-mq-sched.c:338
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:358
 __blk_mq_run_hw_queue+0xc1/0x140 block/blk-mq.c:1785
 blk_mq_run_work_fn+0x3d/0x50 block/blk-mq.c:2117
 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
 worker_thread+0x616/0xa70 kernel/workqueue.c:2445
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

value changed: 0x0000000100006bb4 -> 0x00000001000074f7

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 237 Comm: kworker/0:1H Not tainted 5.16.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kblockd blk_mq_run_work_fn
==================================================================

Crashes (8):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/12/31 22:16 upstream 4f3d93c6eaff 36bd2e48 .config log report info KCSAN: data-race in __mod_timer / blk_add_timer
ci2-upstream-kcsan-gce 2021/11/28 03:45 upstream 741392771338 63eeac02 .config log report info KCSAN: data-race in __mod_timer / blk_add_timer
ci2-upstream-kcsan-gce 2021/11/01 17:20 upstream 8bb7eca972ad 098b5d53 .config log report info KCSAN: data-race in __mod_timer / blk_add_timer
ci2-upstream-kcsan-gce 2021/10/26 19:44 upstream 3906fe9bb7f1 d50eb50a .config log report info KCSAN: data-race in __mod_timer / blk_add_timer
ci2-upstream-kcsan-gce 2021/10/24 15:02 upstream 9c0c4d24ac00 282f03fb .config log report info KCSAN: data-race in __mod_timer / blk_add_timer
ci2-upstream-kcsan-gce 2021/10/16 13:26 upstream 8fe31e0995f0 0c5d9412 .config log report info KCSAN: data-race in __mod_timer / blk_add_timer
ci2-upstream-kcsan-gce 2021/10/08 09:42 upstream 1da38549dd64 efe0f24d .config log report info KCSAN: data-race in __mod_timer / blk_add_timer
ci2-upstream-kcsan-gce 2021/09/24 13:35 upstream f9e36107ec70 8cac236e .config log report info KCSAN: data-race in __mod_timer / blk_add_timer
* Struck through repros no longer work on HEAD.