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BUG: KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_run_hw_queue

write to 0xffff888128ff8010 of 8 bytes by task 3230 on cpu 0:
 INIT_LIST_HEAD include/linux/list.h:36 [inline]
 list_splice_init include/linux/list.h:465 [inline]
 __blk_mq_sched_dispatch_requests+0x174/0x2b0 block/blk-mq-sched.c:224
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:276
 __blk_mq_run_hw_queue+0xee/0x1c0 block/blk-mq.c:1418
 __blk_mq_delay_run_hw_queue+0x199/0x340 block/blk-mq.c:1495
 blk_mq_run_hw_queue+0x22e/0x260 block/blk-mq.c:1548
 blk_mq_run_hw_queues block/blk-mq.c:1566 [inline]
 blk_mq_requeue_work+0x433/0x4a0 block/blk-mq.c:774
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

read to 0xffff888128ff8010 of 8 bytes by interrupt on cpu 1:
 list_empty_careful include/linux/list.h:301 [inline]
 blk_mq_hctx_has_pending block/blk-mq.c:70 [inline]
 blk_mq_run_hw_queue+0x12b/0x260 block/blk-mq.c:1544
 blk_mq_run_hw_queues+0xa2/0x100 block/blk-mq.c:1566
 scsi_run_queue_async drivers/scsi/scsi_lib.c:556 [inline]
 scsi_end_request+0x386/0x400 drivers/scsi/scsi_lib.c:603
 scsi_io_completion+0x105/0xf40 drivers/scsi/scsi_lib.c:939
 scsi_finish_command+0x277/0x2c0 drivers/scsi/scsi.c:214
 scsi_softirq_done+0x271/0x400 drivers/scsi/scsi_lib.c:1465
 blk_done_softirq+0x1a5/0x200 block/blk-softirq.c:37
 __do_softirq+0x198/0x360 kernel/softirq.c:292
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 __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:387 [inline]
 __irq_exit_rcu+0x115/0x120 kernel/softirq.c:417
 common_interrupt+0x14e/0x1e0 arch/x86/kernel/irq.c:239
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:576
 preempt_count arch/x86/include/asm/preempt.h:26 [inline]
 check_kcov_mode kernel/kcov.c:163 [inline]
 __sanitizer_cov_trace_pc+0x14/0x60 kernel/kcov.c:197
 release_pages+0x1b7/0x8c0 mm/swap.c:871
 __pagevec_release+0x96/0xc0 mm/swap.c:931
 pagevec_release include/linux/pagevec.h:88 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2334 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2469 [inline]
 ext4_writepages+0xf73/0x1ef0 fs/ext4/inode.c:2782
 do_writepages+0x7b/0x150 mm/page-writeback.c:2354
 __filemap_fdatawrite_range+0x19b/0x1d0 mm/filemap.c:421
 file_write_and_wait_range+0x9f/0x120 mm/filemap.c:760
 ext4_sync_file+0xfc/0x6e0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2882 [inline]
 ext4_buffered_write_iter+0x369/0x3b0 fs/ext4/file.c:277
 ext4_file_write_iter+0x76f/0x1010 include/linux/fs.h:805
 call_write_iter include/linux/fs.h:1908 [inline]
 do_iter_readv_writev+0x321/0x3c0 fs/read_write.c:713
 do_iter_write+0x10e/0x470 fs/read_write.c:1018
 vfs_iter_write+0x4c/0x70 fs/read_write.c:1059
 iter_file_splice_write+0x41a/0x770 fs/splice.c:750
 do_splice_from fs/splice.c:846 [inline]
 direct_splice_actor+0x95/0x160 fs/splice.c:1016
 splice_direct_to_actor+0x365/0x660 fs/splice.c:971
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x562/0xb10 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18029 Comm: syz-executor.5 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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