====================================================== WARNING: possible circular locking dependency detected 4.14.174-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/13732 is trying to acquire lock: ("dio/%s"sb->s_id){+.+.}, at: [] flush_workqueue+0xda/0x13f0 kernel/workqueue.c:2621 but task is already holding lock: (&sb->s_type->i_mutex_key#9){++++}, at: [] inode_trylock include/linux/fs.h:738 [inline] (&sb->s_type->i_mutex_key#9){++++}, at: [] ext4_file_write_iter+0x1d5/0xdc0 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#9){++++}: down_write+0x34/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:718 [inline] __generic_file_fsync+0x9e/0x190 fs/libfs.c:985 ext4_sync_file+0x757/0x12c0 fs/ext4/fsync.c:120 vfs_fsync_range+0x103/0x250 fs/sync.c:196 generic_write_sync include/linux/fs.h:2677 [inline] dio_complete+0x37d/0x840 fs/direct-io.c:330 process_one_work+0x813/0x1540 kernel/workqueue.c:2116 worker_thread+0x5d1/0x1070 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+0x7b5/0x1540 kernel/workqueue.c:2092 worker_thread+0x5d1/0x1070 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:3994 flush_workqueue+0x109/0x13f0 kernel/workqueue.c:2624 drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789 destroy_workqueue+0x71/0x660 kernel/workqueue.c:4102 sb_init_dio_done_wq+0x61/0x80 fs/direct-io.c:635 do_blockdev_direct_IO+0x3842/0x9120 fs/direct-io.c:1286 ext4_direct_IO_write fs/ext4/inode.c:3712 [inline] ext4_direct_IO+0x7cf/0x1980 fs/ext4/inode.c:3848 generic_file_direct_write+0x1df/0x420 mm/filemap.c:2950 __generic_file_write_iter+0x2a5/0x590 mm/filemap.c:3129 ext4_file_write_iter+0x281/0xdc0 fs/ext4/file.c:270 call_write_iter include/linux/fs.h:1777 [inline] aio_write+0x2c7/0x4f0 fs/aio.c:1553 io_submit_one fs/aio.c:1641 [inline] do_io_submit+0x996/0x13f0 fs/aio.c:1709 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 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#9 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#9); lock((&dio->complete_work)); lock(&sb->s_type->i_mutex_key#9); lock("dio/%s"sb->s_id); *** DEADLOCK *** 2 locks held by syz-executor.0/13732: #0: (sb_writers#4){.+.+}, at: [] file_start_write include/linux/fs.h:2707 [inline] #0: (sb_writers#4){.+.+}, at: [] aio_write+0x426/0x4f0 fs/aio.c:1552 #1: (&sb->s_type->i_mutex_key#9){++++}, at: [] inode_trylock include/linux/fs.h:738 [inline] #1: (&sb->s_type->i_mutex_key#9){++++}, at: [] ext4_file_write_iter+0x1d5/0xdc0 fs/ext4/file.c:236 stack backtrace: CPU: 0 PID: 13732 Comm: syz-executor.0 Not tainted 4.14.174-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+0x13e/0x194 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994 flush_workqueue+0x109/0x13f0 kernel/workqueue.c:2624 drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789 destroy_workqueue+0x71/0x660 kernel/workqueue.c:4102 sb_init_dio_done_wq+0x61/0x80 fs/direct-io.c:635 do_blockdev_direct_IO+0x3842/0x9120 fs/direct-io.c:1286 ext4_direct_IO_write fs/ext4/inode.c:3712 [inline] ext4_direct_IO+0x7cf/0x1980 fs/ext4/inode.c:3848 generic_file_direct_write+0x1df/0x420 mm/filemap.c:2950 __generic_file_write_iter+0x2a5/0x590 mm/filemap.c:3129 ext4_file_write_iter+0x281/0xdc0 fs/ext4/file.c:270 call_write_iter include/linux/fs.h:1777 [inline] aio_write+0x2c7/0x4f0 fs/aio.c:1553 io_submit_one fs/aio.c:1641 [inline] do_io_submit+0x996/0x13f0 fs/aio.c:1709 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c849 RSP: 002b:00007f17ff305c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 00007f17ff3066d4 RCX: 000000000045c849 RDX: 0000000020000540 RSI: 0000000000000001 RDI: 00007f17ff2dd000 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000001f9 R14: 00000000004c422b R15: 000000000076bf0c IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21