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BUG: KCSAN: data-race in blk_mq_dispatch_rq_list / blk_mq_dispatch_rq_list

write to 0xffff8881010096f8 of 4 bytes by task 78 on cpu 1:
 blk_mq_dispatch_rq_list+0xf55/0x10a0
 __blk_mq_sched_dispatch_requests+0x1ce/0xd20 block/blk-mq-sched.c:301
 blk_mq_sched_dispatch_requests+0x78/0xe0 block/blk-mq-sched.c:331
 blk_mq_run_hw_queue+0x298/0x4c0 block/blk-mq.c:2285
 blk_mq_run_hw_queues+0x15b/0x1e0 block/blk-mq.c:2334
 blk_mq_requeue_work+0x408/0x430 block/blk-mq.c:1503
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

read to 0xffff8881010096f8 of 4 bytes by task 21208 on cpu 0:
 blk_mq_update_dispatch_busy block/blk-mq.c:1919 [inline]
 blk_mq_dispatch_rq_list+0xcb3/0x10a0 block/blk-mq.c:2170
 __blk_mq_sched_dispatch_requests+0x1ce/0xd20 block/blk-mq-sched.c:301
 blk_mq_sched_dispatch_requests+0x78/0xe0 block/blk-mq-sched.c:331
 blk_mq_run_hw_queue+0x298/0x4c0 block/blk-mq.c:2285
 blk_mq_flush_plug_list+0x7a7/0xdc0 block/blk-mq.c:2833
 __blk_flush_plug+0x210/0x260 block/blk-core.c:1176
 blk_finish_plug+0x47/0x60 block/blk-core.c:1200
 ext4_do_writepages+0x1bc9/0x2100 fs/ext4/inode.c:2730
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2768
 do_writepages+0x1c2/0x340 mm/page-writeback.c:2553
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 filemap_write_and_wait_range+0xe0/0x210 mm/filemap.c:676
 filemap_write_and_wait include/linux/pagemap.h:64 [inline]
 ext4_bmap+0x14e/0x180 fs/ext4/inode.c:3109
 bmap+0x5a/0x80 fs/inode.c:1790
 ioctl_fibmap fs/ioctl.c:77 [inline]
 file_ioctl fs/ioctl.c:328 [inline]
 do_vfs_ioctl+0x11b5/0x13a0 fs/ioctl.c:850
 __do_sys_ioctl fs/ioctl.c:869 [inline]
 __se_sys_ioctl+0x81/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000003 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21208 Comm: syz-executor.3 Not tainted 6.8.0-rc4-syzkaller-00014-g7e90b5c295ec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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