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BUG: KCSAN: data-race in __blk_mq_alloc_driver_tag / blk_mq_tagset_busy_iter

write to 0xffff8881035913a0 of 4 bytes by task 403 on cpu 0:
 __blk_mq_alloc_driver_tag+0x181/0x380 block/blk-mq.c:1869
 blk_mq_get_driver_tag block/blk-mq.h:374 [inline]
 blk_mq_prep_dispatch_rq block/blk-mq.c:2042 [inline]
 blk_mq_dispatch_rq_list+0x1a6/0xef0 block/blk-mq.c:2121
 __blk_mq_sched_dispatch_requests+0x1db/0xce0 block/blk-mq-sched.c:299
 blk_mq_sched_dispatch_requests+0x86/0x120 block/blk-mq-sched.c:329
 blk_mq_run_work_fn+0x66/0xe0 block/blk-mq.c:2545
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3479
 worker_thread+0x569/0x750 kernel/workqueue.c:3560
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff8881035913a0 of 4 bytes by task 2945 on cpu 1:
 blk_mq_find_and_get_req block/blk-mq-tag.c:267 [inline]
 bt_tags_iter block/blk-mq-tag.c:362 [inline]
 __sbitmap_for_each_set include/linux/sbitmap.h:269 [inline]
 sbitmap_for_each_set include/linux/sbitmap.h:290 [inline]
 bt_tags_for_each block/blk-mq-tag.c:397 [inline]
 __blk_mq_all_tag_iter block/blk-mq-tag.c:408 [inline]
 blk_mq_tagset_busy_iter+0x673/0x890 block/blk-mq-tag.c:452
 scsi_host_busy+0x4e/0x80 drivers/scsi/hosts.c:632
 scsi_host_queue_ready drivers/scsi/scsi_lib.c:1490 [inline]
 scsi_queue_rq+0x4ec/0x1a20 drivers/scsi/scsi_lib.c:1890
 blk_mq_dispatch_rq_list+0x5d2/0xef0 block/blk-mq.c:2130
 __blk_mq_sched_dispatch_requests+0x1db/0xce0 block/blk-mq-sched.c:299
 blk_mq_sched_dispatch_requests+0x86/0x120 block/blk-mq-sched.c:329
 blk_mq_run_hw_queue+0x17d/0x220 block/blk-mq.c:2369
 blk_mq_run_hw_queues+0x18e/0x270 block/blk-mq.c:2417
 blk_mq_requeue_work+0x3ca/0x400 block/blk-mq.c:1584
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3479
 worker_thread+0x569/0x750 kernel/workqueue.c:3560
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0xffffffff -> 0x00000c4e

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2945 Comm: kworker/1:1H Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: kblockd blk_mq_requeue_work
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