syzbot

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BUG: KCSAN: data-race in blk_mq_dispatch_rq_list / blk_mq_dispatch_rq_list

read to 0xffff888101ff72f8 of 4 bytes by task 227 on cpu 1:
 blk_mq_update_dispatch_busy block/blk-mq.c:1697 [inline]
 blk_mq_dispatch_rq_list+0xfe4/0x1140 block/blk-mq.c:1946
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:173 [inline]
 blk_mq_do_dispatch_sched+0x446/0x6d0 block/blk-mq-sched.c:186
 __blk_mq_sched_dispatch_requests+0x1ca/0x270
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:332
 __blk_mq_run_hw_queue+0x7e/0x100 block/blk-mq.c:1968
 blk_mq_run_work_fn+0x3d/0x50 block/blk-mq.c:2298
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

write to 0xffff888101ff72f8 of 4 bytes by task 15564 on cpu 0:
 blk_mq_update_dispatch_busy block/blk-mq.c:1707 [inline]
 blk_mq_dispatch_rq_list+0xd71/0x1140 block/blk-mq.c:1949
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:173 [inline]
 blk_mq_do_dispatch_sched+0x446/0x6d0 block/blk-mq-sched.c:186
 __blk_mq_sched_dispatch_requests+0x1ca/0x270
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:332
 __blk_mq_run_hw_queue+0x7e/0x100 block/blk-mq.c:1968
 __blk_mq_delay_run_hw_queue+0x19c/0x390 block/blk-mq.c:2045
 blk_mq_run_hw_queue+0x180/0x310 block/blk-mq.c:2096
 blk_mq_sched_insert_requests+0x1cc/0x2a0 block/blk-mq-sched.c:486
 blk_mq_flush_plug_list+0x5c3/0x6c0 block/blk-mq.c:2628
 blk_add_rq_to_plug+0x13f/0x3a0 block/blk-mq.c:2690
 blk_mq_submit_bio+0x8c7/0xe50 block/blk-mq.c:2831
 __submit_bio+0x151/0x350 block/blk-core.c:806
 __submit_bio_noacct_mq block/blk-core.c:881 [inline]
 submit_bio_noacct+0x475/0x4e0 block/blk-core.c:907
 submit_bio+0x10c/0x180
 iomap_dio_submit_bio fs/iomap/direct-io.c:66 [inline]
 iomap_dio_bio_iter+0x9ed/0xc70 fs/iomap/direct-io.c:351
 __iomap_dio_rw+0x915/0x10b0 fs/iomap/direct-io.c:590
 iomap_dio_rw+0x38/0x80 fs/iomap/direct-io.c:680
 ext4_dio_write_iter fs/ext4/file.c:564 [inline]
 ext4_file_write_iter+0x7d5/0xda0 fs/ext4/file.c:675
 call_write_iter include/linux/fs.h:2074 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x7f5/0x950 fs/read_write.c:590
 ksys_write+0xd9/0x190 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000007 -> 0x00000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15564 Comm: syz-executor.0 Not tainted 5.17.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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