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BUG: KCSAN: data-race in blk_mq_dispatch_rq_list / blk_mq_dispatch_rq_list

write to 0xffff8881299a7560 of 8 bytes by task 18646 on cpu 0:
 blk_mq_dispatch_rq_list+0x4d9/0xe40 block/blk-mq.c:1298
 blk_mq_do_dispatch_sched+0x11d/0x260 block/blk-mq-sched.c:115
 blk_mq_sched_dispatch_requests+0x2b4/0x380 block/blk-mq-sched.c:211
 __blk_mq_run_hw_queue+0xb7/0x160 block/blk-mq.c:1403
 __blk_mq_delay_run_hw_queue+0x31b/0x3a0 block/blk-mq.c:1471
 blk_mq_run_hw_queue+0x103/0x1c0 block/blk-mq.c:1508
 blk_mq_sched_insert_requests+0x1ca/0x2e0 block/blk-mq-sched.c:444
 blk_mq_flush_plug_list+0x572/0x6c0 block/blk-mq.c:1772
 blk_flush_plug_list+0x271/0x2a0 block/blk-core.c:1766
 blk_finish_plug block/blk-core.c:1783 [inline]
 blk_finish_plug+0x60/0x84 block/blk-core.c:1779
 do_blockdev_direct_IO+0x48b6/0x78c0 fs/direct-io.c:1355
 __blockdev_direct_IO+0x86/0xa0 fs/direct-io.c:1412
 ext4_direct_IO_write fs/ext4/inode.c:3742 [inline]
 ext4_direct_IO+0x6f5/0xf70 fs/ext4/inode.c:3871
 generic_file_direct_write+0x14d/0x2e0 mm/filemap.c:3207

read to 0xffff8881299a7560 of 8 bytes by task 18647 on cpu 1:
 blk_mq_dispatch_rq_list+0x4c4/0xe40 block/blk-mq.c:1298
 blk_mq_do_dispatch_sched+0x11d/0x260 block/blk-mq-sched.c:115
 blk_mq_sched_dispatch_requests+0x2b4/0x380 block/blk-mq-sched.c:211
 __blk_mq_run_hw_queue+0xb7/0x160 block/blk-mq.c:1403
 __blk_mq_delay_run_hw_queue+0x31b/0x3a0 block/blk-mq.c:1471
 blk_mq_run_hw_queue+0x103/0x1c0 block/blk-mq.c:1508
 blk_mq_sched_insert_requests+0x1ca/0x2e0 block/blk-mq-sched.c:444
 blk_mq_flush_plug_list+0x572/0x6c0 block/blk-mq.c:1772
 blk_flush_plug_list+0x271/0x2a0 block/blk-core.c:1766
 blk_finish_plug block/blk-core.c:1783 [inline]
 blk_finish_plug+0x60/0x84 block/blk-core.c:1779
 do_blockdev_direct_IO+0x48b6/0x78c0 fs/direct-io.c:1355
 __blockdev_direct_IO+0x86/0xa0 fs/direct-io.c:1412
 ext4_direct_IO_write fs/ext4/inode.c:3742 [inline]
 ext4_direct_IO+0x6f5/0xf70 fs/ext4/inode.c:3871

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18647 Comm: syz-executor.2 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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