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BUG: KCSAN: data-race in blk_mq_run_hw_queue / blk_mq_sched_insert_request

write to 0xffff88812a986810 of 8 bytes by task 2520 on cpu 0:
 __list_add include/linux/list.h:70 [inline]
 list_add include/linux/list.h:86 [inline]
 blk_mq_sched_bypass_insert block/blk-mq-sched.c:367 [inline]
 blk_mq_sched_insert_request+0x2f2/0x3e0 block/blk-mq-sched.c:394
 blk_mq_requeue_work+0x347/0x440 block/blk-mq.c:746
 process_one_work+0x424/0x930 kernel/workqueue.c:2264
 worker_thread+0x9a/0x7e0 kernel/workqueue.c:2410
 kthread+0x1cb/0x1f0 kernel/kthread.c:255
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff88812a986810 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:69 [inline]
 blk_mq_run_hw_queue+0x10a/0x1b0 block/blk-mq.c:1508
 blk_mq_run_hw_queues+0xa2/0xe0 block/blk-mq.c:1530
 scsi_end_request+0x338/0x350 drivers/scsi/scsi_lib.c:616
 scsi_io_completion+0x11e/0xcc0 drivers/scsi/scsi_lib.c:960
 scsi_finish_command+0x283/0x390 drivers/scsi/scsi.c:228
 scsi_softirq_done+0x249/0x270 drivers/scsi/scsi_lib.c:1476
 blk_done_softirq+0x1e6/0x250 block/blk-softirq.c:37
 __do_softirq+0x118/0x34a kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xb5/0xd0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 do_IRQ+0x7b/0x120 arch/x86/kernel/irq.c:263
 ret_from_intr+0x0/0x21
 __sanitizer_cov_trace_pc+0x44/0x50 kernel/kcov.c:194
 __blk_mq_delay_run_hw_queue+0x49/0x390 block/blk-mq.c:1456
 blk_mq_run_hw_queue+0xfa/0x1b0 block/blk-mq.c:1512
 blk_mq_sched_insert_request+0x278/0x3e0 block/blk-mq-sched.c:410
 blk_mq_make_request+0x78c/0xf60 block/blk-mq.c:2067
 generic_make_request block/blk-core.c:1069 [inline]
 generic_make_request+0x196/0x700 block/blk-core.c:1011
 submit_bio+0x8f/0x3a0 block/blk-core.c:1195
 submit_bh_wbc+0x40d/0x460 fs/buffer.c:3112
 submit_bh fs/buffer.c:3118 [inline]
 __sync_dirty_buffer+0xd9/0x210 fs/buffer.c:3204
 sync_dirty_buffer+0x21/0x30 fs/buffer.c:3217
 ext4_write_inode+0x31a/0x330 fs/ext4/inode.c:5120
 write_inode fs/fs-writeback.c:1312 [inline]
 __writeback_single_inode+0x722/0x910 fs/fs-writeback.c:1511
 writeback_single_inode+0x219/0x2f0 fs/fs-writeback.c:1565
 sync_inode fs/fs-writeback.c:2602 [inline]
 sync_inode_metadata+0x75/0xa0 fs/fs-writeback.c:2622
 ext4_fsync_nojournal fs/ext4/fsync.c:94 [inline]
 ext4_sync_file+0x47a/0x8b0 fs/ext4/fsync.c:172
 vfs_fsync_range+0x7c/0x150 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2867 [inline]
 iomap_dio_complete+0x37a/0x3c0 fs/iomap/direct-io.c:120
 iomap_dio_rw+0x8e3/0x9a0 fs/iomap/direct-io.c:569
 ext4_dio_write_iter fs/ext4/file.c:532 [inline]
 ext4_file_write_iter+0xb84/0xd30 fs/ext4/file.c:640
 call_write_iter include/linux/fs.h:1901 [inline]
 do_iter_readv_writev+0x4a7/0x5d0 fs/read_write.c:693
 do_iter_write fs/read_write.c:998 [inline]
 do_iter_write+0x137/0x3a0 fs/read_write.c:979
 vfs_iter_write+0x56/0x80 fs/read_write.c:1039
 iter_file_splice_write+0x530/0x830 fs/splice.c:760
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0x97/0xb0 fs/splice.c:1037
 splice_direct_to_actor+0x22f/0x540 fs/splice.c:992
 do_splice_direct+0x152/0x1d0 fs/splice.c:1080
 do_sendfile+0x396/0x810 fs/read_write.c:1520
 __do_sys_sendfile64 fs/read_write.c:1581 [inline]
 __se_sys_sendfile64 fs/read_write.c:1567 [inline]
 __x64_sys_sendfile64+0x121/0x140 fs/read_write.c:1567
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28293 Comm: syz-executor.4 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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