Bluetooth: hci5 command 0x0419 tx timeout
hrtimer: interrupt took 26566 ns
Bluetooth: hci3 command 0x0419 tx timeout
Bluetooth: hci4 command 0x0419 tx timeout
======================================================
WARNING: possible circular locking dependency detected
4.14.216-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/9478 is trying to acquire lock:
 ("dio/%s"sb->s_id){+.+.}, at: [<ffffffff8135a24b>] flush_workqueue+0xcb/0x1310 kernel/workqueue.c:2621

but task is already holding lock:
 (&sb->s_type->i_mutex_key#10){+.+.}, at: [<ffffffff81b6fc5c>] inode_trylock include/linux/fs.h:739 [inline]
 (&sb->s_type->i_mutex_key#10){+.+.}, at: [<ffffffff81b6fc5c>] 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: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: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:4109
       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:3725 [inline]
       ext4_direct_IO+0x888/0x1b80 fs/ext4/inode.c:3866
       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: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 syz-executor.0/9478:
 #0:  (sb_writers#3){.+.+}, at: [<ffffffff8197c3b8>] file_start_write include/linux/fs.h:2712 [inline]
 #0:  (sb_writers#3){.+.+}, at: [<ffffffff8197c3b8>] aio_write+0x408/0x560 fs/aio.c:1552
 #1:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<ffffffff81b6fc5c>] inode_trylock include/linux/fs.h:739 [inline]
 #1:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<ffffffff81b6fc5c>] ext4_file_write_iter+0x1cc/0xd20 fs/ext4/file.c:236

stack backtrace:
CPU: 1 PID: 9478 Comm: syz-executor.0 Not tainted 4.14.216-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+0x1b2/0x281 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
 flush_workqueue+0xfa/0x1310 kernel/workqueue.c:2624
 drain_workqueue+0x177/0x3e0 kernel/workqueue.c:2789
 destroy_workqueue+0x71/0x710 kernel/workqueue.c:4109
 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:3725 [inline]
 ext4_direct_IO+0x888/0x1b80 fs/ext4/inode.c:3866
 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: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: 0033:0x45e219
RSP: 002b:00007f91e5118c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 00000000200003c0 RSI: 00000000000041e3 RDI: 00007f91e50f6000
RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffe46ed3f3f R14: 00007f91e51199c0 R15: 000000000119bf8c
Bluetooth: hci0 command 0x0419 tx timeout