================================================================== BUG: KCSAN: data-race in dd_has_work / dd_insert_requests write to 0xffff8881039241a8 of 8 bytes by task 16747 on cpu 0: __list_add include/linux/list.h:70 [inline] list_add_tail include/linux/list.h:100 [inline] dd_insert_request block/mq-deadline.c:521 [inline] dd_insert_requests+0x38e/0x4f0 block/mq-deadline.c:537 blk_mq_sched_insert_requests+0xc3/0x210 block/blk-mq-sched.c:486 blk_mq_flush_plug_list+0x2f5/0x400 block/blk-mq.c:1915 blk_flush_plug_list+0x235/0x260 block/blk-core.c:1755 blk_finish_plug+0x44/0x60 block/blk-core.c:1772 ext4_writepages+0x18dd/0x1e70 fs/ext4/inode.c:2852 do_writepages+0x7b/0x150 mm/page-writeback.c:2352 __filemap_fdatawrite_range+0x19d/0x1d0 mm/filemap.c:422 file_write_and_wait_range+0x9f/0x120 mm/filemap.c:761 ext4_sync_file+0x105/0x6e0 fs/ext4/fsync.c:151 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2737 [inline] ext4_buffered_write_iter+0x38f/0x3e0 fs/ext4/file.c:278 ext4_file_write_iter+0x47a/0x1060 fs/ext4/file.c:503 call_write_iter include/linux/fs.h:1901 [inline] do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740 do_iter_write+0x112/0x4c0 fs/read_write.c:866 vfs_iter_write+0x4c/0x70 fs/read_write.c:907 iter_file_splice_write+0x41a/0x770 fs/splice.c:686 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:933 splice_direct_to_actor+0x345/0x650 fs/splice.c:888 do_splice_direct+0xf5/0x170 fs/splice.c:976 do_sendfile+0x5e0/0xcf0 fs/read_write.c:1257 __do_sys_sendfile64 fs/read_write.c:1312 [inline] __se_sys_sendfile64 fs/read_write.c:1304 [inline] __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1304 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8881039241a8 of 8 bytes by task 2049 on cpu 1: list_empty_careful include/linux/list.h:319 [inline] dd_has_work+0xfe/0x110 block/mq-deadline.c:590 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:135 [inline] blk_mq_do_dispatch_sched+0x138/0x610 block/blk-mq-sched.c:199 __blk_mq_sched_dispatch_requests+0x1fd/0x2a0 block/blk-mq-sched.c:310 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:341 __blk_mq_run_hw_queue block/blk-mq.c:1515 [inline] __blk_mq_delay_run_hw_queue+0x207/0x420 block/blk-mq.c:1592 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1645 blk_mq_run_hw_queues block/blk-mq.c:1663 [inline] blk_mq_requeue_work+0x423/0x490 block/blk-mq.c:824 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275 worker_thread+0x616/0xa70 kernel/workqueue.c:2421 kthread+0x20b/0x230 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 2049 Comm: kworker/1:1H Not tainted 5.11.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: kblockd blk_mq_requeue_work ==================================================================