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BUG: KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_run_hw_queue

write to 0xffff888129a12810 of 8 bytes by task 3256 on cpu 0:
 INIT_LIST_HEAD include/linux/list.h:36 [inline]
 list_splice_init include/linux/list.h:483 [inline]
 __blk_mq_sched_dispatch_requests+0x16a/0x2a0 block/blk-mq-sched.c:304
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:356
 __blk_mq_run_hw_queue+0xee/0x1c0 block/blk-mq.c:1534
 __blk_mq_delay_run_hw_queue+0x199/0x340 block/blk-mq.c:1611
 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1664
 blk_mq_run_hw_queues block/blk-mq.c:1682 [inline]
 blk_mq_requeue_work+0x423/0x490 block/blk-mq.c:816
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff888129a12810 of 8 bytes by interrupt on cpu 1:
 list_empty_careful include/linux/list.h:319 [inline]
 blk_mq_hctx_has_pending block/blk-mq.c:72 [inline]
 blk_mq_run_hw_queue+0x12e/0x260 block/blk-mq.c:1660
 blk_mq_run_hw_queues+0xa2/0x100 block/blk-mq.c:1682
 scsi_run_queue_async drivers/scsi/scsi_lib.c:555 [inline]
 scsi_end_request+0x386/0x400 drivers/scsi/scsi_lib.c:602
 scsi_io_completion+0x105/0xf40 drivers/scsi/scsi_lib.c:938
 scsi_finish_command+0x277/0x2c0 drivers/scsi/scsi.c:214
 scsi_softirq_done+0x271/0x400 drivers/scsi/scsi_lib.c:1464
 blk_done_softirq+0x1a5/0x200 block/blk-mq.c:586
 __do_softirq+0x198/0x360 kernel/softirq.c:298
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 do_softirq_own_stack+0x5d/0x80 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu+0x115/0x120 kernel/softirq.c:423
 common_interrupt+0x14e/0x1e0 arch/x86/kernel/irq.c:239
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:572
 arch_local_irq_enable arch/x86/include/asm/paravirt.h:780 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
 _raw_spin_unlock_irq+0x41/0x70 kernel/locking/spinlock.c:199
 finish_lock_switch kernel/sched/core.c:3517 [inline]
 finish_task_switch+0x8b/0x270 kernel/sched/core.c:3617
 context_switch kernel/sched/core.c:3781 [inline]
 __schedule+0x3c5/0x590 kernel/sched/core.c:4527
 schedule_idle+0x27/0x40 kernel/sched/core.c:4630
 do_idle+0x2d4/0x310 kernel/sched/idle.c:304
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:372
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.9.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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