syzbot

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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
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