================================================================== BUG: KCSAN: data-race in __blk_mq_sched_dispatch_requests / blk_mq_run_hw_queue write to 0xffff88812977b410 of 8 bytes by task 3221 on cpu 1: INIT_LIST_HEAD include/linux/list.h:36 [inline] list_splice_init include/linux/list.h:465 [inline] __blk_mq_sched_dispatch_requests+0x174/0x2b0 block/blk-mq-sched.c:224 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:276 __blk_mq_run_hw_queue+0xee/0x1c0 block/blk-mq.c:1418 __blk_mq_delay_run_hw_queue+0x199/0x340 block/blk-mq.c:1495 blk_mq_run_hw_queue+0x22e/0x260 block/blk-mq.c:1548 blk_mq_run_hw_queues block/blk-mq.c:1566 [inline] blk_mq_requeue_work+0x433/0x4a0 block/blk-mq.c:774 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415 kthread+0x20d/0x230 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 read to 0xffff88812977b410 of 8 bytes by task 28333 on cpu 0: list_empty_careful include/linux/list.h:301 [inline] blk_mq_hctx_has_pending block/blk-mq.c:70 [inline] blk_mq_run_hw_queue+0x12b/0x260 block/blk-mq.c:1544 blk_mq_sched_insert_request+0x2ae/0x330 block/blk-mq-sched.c:496 blk_mq_make_request+0x716/0x1070 block/blk-mq.c:2106 do_make_request block/blk-core.c:1084 [inline] generic_make_request+0x240/0x5d0 block/blk-core.c:1156 submit_bio+0x200/0x370 block/blk-core.c:1275 submit_bh_wbc+0x397/0x3d0 fs/buffer.c:3073 submit_bh fs/buffer.c:3079 [inline] __sync_dirty_buffer+0xfa/0x1a0 fs/buffer.c:3165 sync_dirty_buffer+0x16/0x20 fs/buffer.c:3178 ext4_write_inode+0x216/0x330 fs/ext4/inode.c:5165 write_inode+0x8e/0x250 fs/fs-writeback.c:1312 __writeback_single_inode+0x31c/0x610 fs/fs-writeback.c:1511 writeback_single_inode+0x121/0x530 fs/fs-writeback.c:1565 sync_inode fs/fs-writeback.c:2602 [inline] sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2622 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline] ext4_sync_file+0x335/0x6e0 fs/ext4/fsync.c:170 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2882 [inline] ext4_buffered_write_iter+0x369/0x3b0 fs/ext4/file.c:277 ext4_file_write_iter+0x76f/0x1010 include/linux/fs.h:804 call_write_iter include/linux/fs.h:1907 [inline] do_iter_readv_writev+0x321/0x3c0 fs/read_write.c:694 do_iter_write+0x10e/0x470 fs/read_write.c:999 vfs_iter_write+0x4c/0x70 fs/read_write.c:1040 iter_file_splice_write+0x41a/0x770 fs/splice.c:750 do_splice_from fs/splice.c:846 [inline] direct_splice_actor+0x95/0x160 fs/splice.c:1016 splice_direct_to_actor+0x365/0x660 fs/splice.c:971 do_splice_direct+0xf2/0x170 fs/splice.c:1059 do_sendfile+0x562/0xb10 fs/read_write.c:1521 __do_sys_sendfile64 fs/read_write.c:1576 [inline] __se_sys_sendfile64 fs/read_write.c:1568 [inline] __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1568 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 28333 Comm: syz-executor.0 Not tainted 5.8.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================