====================================================== WARNING: possible circular locking dependency detected 4.14.202-syzkaller #0 Not tainted ------------------------------------------------------ //selinux/19963 is trying to acquire lock: ("dio/%s"sb->s_id){+.+.}, at: [] flush_workqueue+0xcb/0x1310 kernel/workqueue.c:2621 but task is already holding lock: (&sb->s_type->i_mutex_key#10){++++}, at: [] inode_trylock include/linux/fs.h:739 [inline] (&sb->s_type->i_mutex_key#10){++++}, at: [] ext4_file_write_iter+0x1cc/0xd20 fs/ext4/file.c:236 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sb->s_type->i_mutex_key#10){++++}: 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:987 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:2682 [inline] dio_complete+0x561/0x8d0 fs/direct-io.c:330 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #1 ((&dio->complete_work)){+.+.}: process_one_work+0x736/0x14a0 kernel/workqueue.c:2092 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #0 ("dio/%s"sb->s_id){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 flush_workqueue+0xfa/0x1310 kernel/workqueue.c:2624 drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789 destroy_workqueue+0x71/0x710 kernel/workqueue.c:4102 sb_init_dio_done_wq+0x61/0x80 fs/direct-io.c:635 do_blockdev_direct_IO fs/direct-io.c:1286 [inline] __blockdev_direct_IO+0x3dea/0xdc60 fs/direct-io.c:1422 ext4_direct_IO_write fs/ext4/inode.c:3716 [inline] ext4_direct_IO+0x888/0x1b80 fs/ext4/inode.c:3857 generic_file_direct_write+0x1df/0x420 mm/filemap.c:2958 __generic_file_write_iter+0x2a2/0x590 mm/filemap.c:3137 ext4_file_write_iter+0x276/0xd20 fs/ext4/file.c:270 call_write_iter include/linux/fs.h:1778 [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 other info that might help us debug this: Chain exists of: "dio/%s"sb->s_id --> (&dio->complete_work) --> &sb->s_type->i_mutex_key#10 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#10); lock((&dio->complete_work)); lock(&sb->s_type->i_mutex_key#10); lock("dio/%s"sb->s_id); *** DEADLOCK *** 2 locks held by //selinux/19963: #0: (sb_writers#3){.+.+}, at: [] file_start_write include/linux/fs.h:2712 [inline] #0: (sb_writers#3){.+.+}, at: [] aio_write+0x408/0x560 fs/aio.c:1552 #1: (&sb->s_type->i_mutex_key#10){++++}, at: [] inode_trylock include/linux/fs.h:739 [inline] #1: (&sb->s_type->i_mutex_key#10){++++}, at: [] ext4_file_write_iter+0x1cc/0xd20 fs/ext4/file.c:236 stack backtrace: CPU: 1 PID: 19963 Comm: //selinux Not tainted 4.14.202-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 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 flush_workqueue+0xfa/0x1310 kernel/workqueue.c:2624 drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789 destroy_workqueue+0x71/0x710 kernel/workqueue.c:4102 sb_init_dio_done_wq+0x61/0x80 fs/direct-io.c:635 do_blockdev_direct_IO fs/direct-io.c:1286 [inline] __blockdev_direct_IO+0x3dea/0xdc60 fs/direct-io.c:1422 ext4_direct_IO_write fs/ext4/inode.c:3716 [inline] ext4_direct_IO+0x888/0x1b80 fs/ext4/inode.c:3857 generic_file_direct_write+0x1df/0x420 mm/filemap.c:2958 __generic_file_write_iter+0x2a2/0x590 mm/filemap.c:3137 ext4_file_write_iter+0x276/0xd20 fs/ext4/file.c:270 call_write_iter include/linux/fs.h:1778 [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 RIP: 0033:0x45de59 RSP: 002b:00007f663f57bc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 0000000000008280 RCX: 000000000045de59 RDX: 0000000020000540 RSI: 0000000000000006 RDI: 00007f663f559000 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffd6f1bb2ef R14: 00007f663f57c9c0 R15: 000000000118bf2c