====================================================== WARNING: possible circular locking dependency detected 4.14.262-syzkaller #0 Not tainted ------------------------------------------------------ kworker/1:3/8669 is trying to acquire lock: (&sb->s_type->i_mutex_key#10){++++}, at: [] inode_lock include/linux/fs.h:719 [inline] (&sb->s_type->i_mutex_key#10){++++}, at: [] __generic_file_fsync+0x9e/0x190 fs/libfs.c:989 but task is already holding lock: ((&dio->complete_work)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 ((&dio->complete_work)){+.+.}: process_one_work+0x736/0x14a0 kernel/workqueue.c:2093 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #1 ("dio/%s"sb->s_id){+.+.}: flush_workqueue+0xfa/0x1310 kernel/workqueue.c:2625 drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2790 destroy_workqueue+0x71/0x710 kernel/workqueue.c:4116 __alloc_workqueue_key+0xd50/0x1080 kernel/workqueue.c:4093 sb_init_dio_done_wq+0x34/0x80 fs/direct-io.c:624 do_blockdev_direct_IO fs/direct-io.c:1287 [inline] __blockdev_direct_IO+0x3df1/0xdcb0 fs/direct-io.c:1423 ext4_direct_IO_write fs/ext4/inode.c:3724 [inline] ext4_direct_IO+0x888/0x1b80 fs/ext4/inode.c:3865 generic_file_direct_write+0x1df/0x420 mm/filemap.c:2958 __generic_file_write_iter+0x2a2/0x590 mm/filemap.c:3137 ext4_file_write_iter+0x7c5/0xd20 fs/ext4/file.c:270 call_write_iter include/linux/fs.h:1780 [inline] aio_write+0x2ed/0x560 fs/aio.c:1553 io_submit_one fs/aio.c:1641 [inline] do_io_submit+0x847/0x1570 fs/aio.c:1709 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&sb->s_type->i_mutex_key#10){++++}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 down_write+0x34/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:719 [inline] __generic_file_fsync+0x9e/0x190 fs/libfs.c:989 ext4_sync_file+0x8ed/0x12c0 fs/ext4/fsync.c:118 vfs_fsync_range+0x103/0x260 fs/sync.c:196 generic_write_sync include/linux/fs.h:2684 [inline] dio_complete+0x561/0x8d0 fs/direct-io.c:330 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#10 --> "dio/%s"sb->s_id --> (&dio->complete_work) Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((&dio->complete_work)); lock("dio/%s"sb->s_id); lock((&dio->complete_work)); lock(&sb->s_type->i_mutex_key#10); *** DEADLOCK *** 2 locks held by kworker/1:3/8669: #0: ("dio/%s"sb->s_id){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088 #1: ((&dio->complete_work)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 stack backtrace: CPU: 1 PID: 8669 Comm: kworker/1:3 Not tainted 4.14.262-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: dio/sda1 dio_aio_complete_work Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 down_write+0x34/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:719 [inline] __generic_file_fsync+0x9e/0x190 fs/libfs.c:989 ext4_sync_file+0x8ed/0x12c0 fs/ext4/fsync.c:118 vfs_fsync_range+0x103/0x260 fs/sync.c:196 generic_write_sync include/linux/fs.h:2684 [inline] dio_complete+0x561/0x8d0 fs/direct-io.c:330 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 kvm: emulating exchange as write print_req_error: I/O error, dev loop2, sector 0 print_req_error: I/O error, dev loop2, sector 0 Buffer I/O error on dev loop2, logical block 0, async page read EXT4-fs (loop2): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop2): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop2): mounted filesystem without journal. Opts: ,errors=continue SQUASHFS error: squashfs_read_data failed to read block 0x0 squashfs: SQUASHFS error: unable to read squashfs_super_block SQUASHFS error: squashfs_read_data failed to read block 0x0 squashfs: SQUASHFS error: unable to read squashfs_super_block SQUASHFS error: squashfs_read_data failed to read block 0x0 squashfs: SQUASHFS error: unable to read squashfs_super_block squashfs: SQUASHFS error: Can't find a SQUASHFS superblock on loop4 squashfs: SQUASHFS error: Can't find a SQUASHFS superblock on loop4