==================================================================
BUG: KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_request_bypass_insert

write to 0xffff88810267e010 of 8 bytes by task 52 on cpu 1:
 __list_add include/linux/list.h:70 [inline]
 list_add include/linux/list.h:86 [inline]
 blk_mq_request_bypass_insert+0x6a/0x150 block/blk-mq.c:1859
 blk_mq_sched_insert_request+0xfc/0x250 block/blk-mq-sched.c:462
 blk_mq_requeue_work+0x3cb/0x440 block/blk-mq.c:795
 process_one_work+0x402/0x910 kernel/workqueue.c:2297
 worker_thread+0x636/0xae0 kernel/workqueue.c:2444
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

read to 0xffff88810267e010 of 8 bytes by task 1317 on cpu 0:
 list_empty_careful include/linux/list.h:319 [inline]
 __blk_mq_sched_dispatch_requests+0x80/0x290 block/blk-mq-sched.c:305
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:360
 __blk_mq_run_hw_queue+0xbc/0x140 block/blk-mq.c:1480
 __blk_mq_delay_run_hw_queue+0x163/0x2f0 block/blk-mq.c:1557
 blk_mq_run_hw_queue+0x22c/0x250 block/blk-mq.c:1610
 blk_mq_sched_insert_requests+0x12b/0x1f0 block/blk-mq-sched.c:513
 blk_mq_flush_plug_list+0x302/0x3d0 block/blk-mq.c:1935
 blk_flush_plug_list+0x235/0x260 block/blk-core.c:1718
 blk_finish_plug+0x44/0x60 block/blk-core.c:1735
 ext4_writepages+0x18f1/0x1d70 fs/ext4/inode.c:2857
 do_writepages+0x26b/0x3c0 mm/page-writeback.c:2364
 filemap_fdatawrite_wbc mm/filemap.c:400 [inline]
 __filemap_fdatawrite_range mm/filemap.c:433 [inline]
 file_write_and_wait_range+0x1ae/0x240 mm/filemap.c:810
 ext4_sync_file+0x105/0x670 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2955 [inline]
 ext4_buffered_write_iter+0x3af/0x400 fs/ext4/file.c:277
 ext4_dio_write_iter fs/ext4/file.c:587 [inline]
 ext4_file_write_iter+0xe79/0x11f0 fs/ext4/file.c:678
 call_write_iter include/linux/fs.h:2163 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:729
 do_iter_write+0x192/0x5c0 fs/read_write.c:855
 vfs_iter_write+0x4c/0x70 fs/read_write.c:896
 iter_file_splice_write+0x43a/0x790 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x63e/0xbb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1314 [inline]
 __se_sys_sendfile64 fs/read_write.c:1300 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1300
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff88810267e008 -> 0xffff888102687c48

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1317 Comm: syz-executor.5 Not tainted 5.15.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
syz-executor.5 (1317) used greatest stack depth: 9984 bytes left