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BUG: KCSAN: data-race in blk_mq_run_hw_queue / blk_mq_sched_dispatch_requests

read to 0xffff88812a90b810 of 8 bytes by interrupt on cpu 1:
 list_empty_careful include/linux/list.h:287 [inline]
 blk_mq_hctx_has_pending block/blk-mq.c:69 [inline]
 blk_mq_run_hw_queue+0x10e/0x1c0 block/blk-mq.c:1469
 blk_mq_run_hw_queues+0xac/0xf0 block/blk-mq.c:1486
 scsi_end_request+0x342/0x360 drivers/scsi/scsi_lib.c:616
 scsi_io_completion+0x11d/0xc80 drivers/scsi/scsi_lib.c:960
 scsi_finish_command+0x283/0x380 drivers/scsi/scsi.c:228
 scsi_softirq_done+0x259/0x280 drivers/scsi/scsi_lib.c:1476
 blk_done_softirq+0x1eb/0x250 block/blk-softirq.c:37
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xbb/0xe0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 do_IRQ+0x81/0x130 arch/x86/kernel/irq.c:263
 ret_from_intr+0x0/0x21
 get_current arch/x86/include/asm/current.h:15 [inline]
 write_comp_data+0x9/0x70 kernel/kcov.c:207
 blk_mq_rq_ctx_init block/blk-mq.c:300 [inline]
 blk_mq_get_request+0x493/0xac0 block/blk-mq.c:385
 blk_mq_make_request+0x2d9/0xf60 block/blk-mq.c:1935
 generic_make_request block/blk-core.c:1066 [inline]
 generic_make_request+0x196/0x700 block/blk-core.c:1008
 submit_bio+0x96/0x3c0 block/blk-core.c:1192
 ext4_io_submit+0xdf/0x110 fs/ext4/page-io.c:384
 ext4_writepages+0x98e/0x2500 fs/ext4/inode.c:2728
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x1c5/0x230 mm/filemap.c:421
 file_write_and_wait_range+0xfd/0x160 mm/filemap.c:782
 ext4_sync_file+0x266/0xaf0 fs/ext4/fsync.c:153
 vfs_fsync_range+0x82/0x150 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2856 [inline]
 ext4_buffered_write_iter+0x222/0x290 fs/ext4/file.c:259
 ext4_file_write_iter+0xf4/0xd40 fs/ext4/file.c:547
 call_write_iter include/linux/fs.h:1902 [inline]
 do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693
 do_iter_write fs/read_write.c:970 [inline]
 do_iter_write+0x13b/0x3c0 fs/read_write.c:951
 vfs_iter_write+0x5c/0x80 fs/read_write.c:983
 iter_file_splice_write+0x530/0x840 fs/splice.c:760
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0xa0/0xc0 fs/splice.c:1037
 splice_direct_to_actor+0x22b/0x540 fs/splice.c:992
 do_splice_direct+0x161/0x1e0 fs/splice.c:1080
 do_sendfile+0x384/0x7f0 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1519 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0xbe/0x140 fs/read_write.c:1511
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88812a90b810 of 8 bytes by task 2499 on cpu 0:
 INIT_LIST_HEAD include/linux/list.h:29 [inline]
 list_splice_init include/linux/list.h:451 [inline]
 blk_mq_sched_dispatch_requests+0x239/0x380 block/blk-mq-sched.c:190
 __blk_mq_run_hw_queue+0xb7/0x160 block/blk-mq.c:1368
 __blk_mq_delay_run_hw_queue+0x31b/0x3a0 block/blk-mq.c:1436
 blk_mq_run_hw_queue+0xfd/0x1c0 block/blk-mq.c:1473
 blk_mq_run_hw_queues+0xac/0xf0 block/blk-mq.c:1486
 blk_mq_requeue_work+0x3a9/0x460 block/blk-mq.c:741
 process_one_work+0x3d4/0x890 kernel/workqueue.c:2264
 worker_thread+0xa0/0x800 kernel/workqueue.c:2410
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2499 Comm: kworker/0:1H Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kblockd blk_mq_requeue_work
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