syzbot

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BUG: KCSAN: data-race in __mod_timer / blk_add_timer

write to 0xffff888101f39448 of 8 bytes by task 78 on cpu 0:
 __mod_timer+0x5a1/0x840 kernel/time/timer.c:1168
 mod_timer+0x1f/0x30 kernel/time/timer.c:1237
 blk_mq_timeout_work+0x177/0x340 block/blk-mq.c:1743
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888101f39448 of 8 bytes by task 47 on cpu 1:
 blk_add_timer+0x115/0x1a0 block/blk-timeout.c:-1
 blk_mq_start_request+0x182/0x390 block/blk-mq.c:1351
 scsi_queue_rq+0x1479/0x19a0 drivers/scsi/scsi_lib.c:1868
 blk_mq_dispatch_rq_list+0x636/0xfe0 block/blk-mq.c:2120
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
 blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
 __blk_mq_sched_dispatch_requests+0x879/0xd10 block/blk-mq-sched.c:309
 blk_mq_sched_dispatch_requests+0x86/0x120 block/blk-mq-sched.c:331
 blk_mq_run_work_fn+0x66/0xe0 block/blk-mq.c:2530
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000ffffd7b4 -> 0x00000000ffffe0f8

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 47 Comm: kworker/1:1H Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: kblockd blk_mq_run_work_fn
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