syzbot

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BUG: KCSAN: data-race in blk_mq_dispatch_rq_list / blk_mq_dispatch_rq_list

write to 0xffff8881028618f8 of 4 bytes by task 1597 on cpu 0:
 blk_mq_update_dispatch_busy block/blk-mq.c:1711 [inline]
 blk_mq_dispatch_rq_list+0xc23/0x11e0 block/blk-mq.c:1953
 __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:1972
 __blk_mq_delay_run_hw_queue+0x19c/0x390 block/blk-mq.c:2049
 blk_mq_run_hw_queue+0x180/0x310 block/blk-mq.c:2100
 blk_mq_sched_insert_requests+0x1cc/0x2a0 block/blk-mq-sched.c:486
 blk_mq_flush_plug_list+0x3fc/0x6c0 block/blk-mq.c:2618
 blk_add_rq_to_plug+0x13f/0x3a0 block/blk-mq.c:2694
 blk_mq_submit_bio+0xa1a/0xff0 block/blk-mq.c:2846
 __submit_bio+0x151/0x350 block/blk-core.c:800
 __submit_bio_noacct_mq block/blk-core.c:875 [inline]
 submit_bio_noacct+0x475/0x4e0 block/blk-core.c:901
 submit_bio+0x10c/0x180
 ext4_io_submit fs/ext4/page-io.c:379 [inline]
 io_submit_add_bh fs/ext4/page-io.c:422 [inline]
 ext4_bio_write_page+0x516/0x720 fs/ext4/page-io.c:550
 mpage_submit_page fs/ext4/inode.c:2080 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2326 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2465 [inline]
 ext4_writepages+0xe76/0x1a60 fs/ext4/inode.c:2778
 do_writepages+0x1cb/0x330 mm/page-writeback.c:2364
 filemap_fdatawrite_wbc mm/filemap.c:384 [inline]
 __filemap_fdatawrite_range mm/filemap.c:417 [inline]
 filemap_write_and_wait_range+0x1b4/0x340 mm/filemap.c:669
 filemap_write_and_wait include/linux/fs.h:2794 [inline]
 ext4_ioctl_setflags fs/ext4/ioctl.c:638 [inline]
 ext4_fileattr_set+0x494/0xc20 fs/ext4/ioctl.c:1002
 vfs_fileattr_set+0x5b7/0x5f0 fs/ioctl.c:700
 do_vfs_ioctl+0x110b/0x14a0
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl+0x83/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 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

read to 0xffff8881028618f8 of 4 bytes by task 227 on cpu 1:
 blk_mq_update_dispatch_busy block/blk-mq.c:1701 [inline]
 blk_mq_dispatch_rq_list+0xbf1/0x11e0 block/blk-mq.c:1953
 __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:1972
 blk_mq_run_work_fn+0x3d/0x50 block/blk-mq.c:2302
 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

value changed: 0x00000002 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 227 Comm: kworker/1:1H Not tainted 5.17.0-rc8-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kblockd blk_mq_run_work_fn
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