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BUG: KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_dispatch_rq_list

write to 0xffff8881001994f8 of 4 bytes by task 42 on cpu 1:
 blk_mq_dispatch_rq_list+0xfa7/0x11b0
 __blk_mq_sched_dispatch_requests+0x1d4/0xdd0 block/blk-mq-sched.c:301
 blk_mq_sched_dispatch_requests+0xb4/0x100 block/blk-mq-sched.c:334
 blk_mq_run_work_fn+0x65/0xe0 block/blk-mq.c:2406
 process_one_work+0x434/0x860 kernel/workqueue.c:2597
 worker_thread+0x5f2/0xa10 kernel/workqueue.c:2748
 kthread+0x1d7/0x210 kernel/kthread.c:389
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

read to 0xffff8881001994f8 of 4 bytes by task 14912 on cpu 0:
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:97 [inline]
 blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
 __blk_mq_sched_dispatch_requests+0x29b/0xdd0 block/blk-mq-sched.c:309
 blk_mq_sched_dispatch_requests+0x99/0x100 block/blk-mq-sched.c:333
 blk_mq_run_hw_queue+0x29c/0x4c0 block/blk-mq.c:2237
 blk_mq_flush_plug_list+0xb55/0xd80 block/blk-mq.c:2780
 blk_add_rq_to_plug+0x108/0x3e0 block/blk-mq.c:1267
 blk_mq_submit_bio+0x692/0xcd0 block/blk-mq.c:2974
 __submit_bio+0x11c/0x350 block/blk-core.c:598
 __submit_bio_noacct_mq block/blk-core.c:677 [inline]
 submit_bio_noacct_nocheck+0x4ad/0x5e0 block/blk-core.c:706
 submit_bio_noacct+0x75c/0x900 block/blk-core.c:805
 submit_bio+0xb7/0xc0 block/blk-core.c:838
 ext4_io_submit fs/ext4/page-io.c:378 [inline]
 io_submit_add_bh fs/ext4/page-io.c:419 [inline]
 ext4_bio_write_folio+0x65f/0x8d0 fs/ext4/page-io.c:563
 mpage_submit_folio fs/ext4/inode.c:1865 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2111 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2251 [inline]
 ext4_do_writepages+0x1416/0x21e0 fs/ext4/inode.c:2677
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2766
 do_writepages+0x1c5/0x340 mm/page-writeback.c:2551
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:393
 __filemap_fdatawrite_range mm/filemap.c:426 [inline]
 file_write_and_wait_range+0xfa/0x190 mm/filemap.c:784
 ext4_sync_file+0x11f/0x6c0 fs/ext4/fsync.c:159
 vfs_fsync_range+0x111/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2493 [inline]
 ext4_buffered_write_iter+0x334/0x370 fs/ext4/file.c:305
 ext4_dio_write_iter fs/ext4/file.c:629 [inline]
 ext4_file_write_iter+0x1047/0x1230 fs/ext4/file.c:720
 do_iter_write+0x4b4/0x7b0 fs/read_write.c:860
 vfs_writev+0x1a8/0x320 fs/read_write.c:933
 do_pwritev fs/read_write.c:1030 [inline]
 __do_sys_pwritev2 fs/read_write.c:1089 [inline]
 __se_sys_pwritev2+0x10c/0x1d0 fs/read_write.c:1080
 __x64_sys_pwritev2+0x78/0x90 fs/read_write.c:1080
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000008 -> 0x00000007

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14912 Comm: syz-executor.5 Not tainted 6.4.0-syzkaller-12069-gc17414a273b8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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syz-executor.5 (14912) used greatest stack depth: 9464 bytes left