Hello,
While testing kernel v4.14-rc7 I encountered the lockedp complaint shown
below. Is this a known issue?
Thanks,
Bart.
======================================================
WARNING: possible circular locking dependency detected
4.14.0-rc7-dbg+ #3 Tainted: G W
------------------------------------------------------
kworker/16:0/20194 is trying to acquire lock:
(&sb->s_type->i_mutex_key#14){+.+.}, at: [<ffffffff812556a9>] __generic_file_fsync+0x49/0xc0
but task is already holding lock:
((&dio->complete_work)){+.+.}, at: [<ffffffff81083b85>] process_one_work+0x195/0x660
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 ((&dio->complete_work)){+.+.}:
lock_acquire+0x95/0x1f0
process_one_work+0x1e7/0x660
worker_thread+0x3d/0x3b0
kthread+0x13a/0x150
ret_from_fork+0x27/0x40
-> #1 ("dio/%s"sb->s_id){+.+.}:
lock_acquire+0x95/0x1f0
flush_workqueue+0x98/0x500
drain_workqueue+0xb0/0x190
destroy_workqueue+0x18/0x260
sb_init_dio_done_wq+0x54/0x60
do_blockdev_direct_IO+0x1c85/0x2f60
__blockdev_direct_IO+0x2e/0x30
ext4_direct_IO+0x2e9/0x7b0 [ext4]
generic_file_direct_write+0xa3/0x160
__generic_file_write_iter+0xbe/0x1d0
ext4_file_write_iter+0x1dd/0x3d0 [ext4]
aio_write+0xf0/0x170
do_io_submit+0x707/0x9b0
SyS_io_submit+0x10/0x20
entry_SYSCALL_64_fastpath+0x18/0xad
-> #0 (&sb->s_type->i_mutex_key#14){+.+.}:
__lock_acquire+0x1248/0x1320
lock_acquire+0x95/0x1f0
down_write+0x3b/0x70
__generic_file_fsync+0x49/0xc0
ext4_sync_file+0x2ac/0x580 [ext4]
vfs_fsync_range+0x4b/0xb0
dio_complete+0x214/0x230
dio_aio_complete_work+0x1c/0x20
process_one_work+0x20a/0x660
worker_thread+0x3d/0x3b0
kthread+0x13a/0x150
ret_from_fork+0x27/0x40
other info that might help us debug this:
Chain exists of:
&sb->s_type->i_mutex_key#14 --> "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#14);
*** DEADLOCK ***
2 locks held by kworker/16:0/20194:
#0: ("dio/%s"sb->s_id){+.+.}, at: [<ffffffff81083b85>] process_one_work+0x195/0x660
#1: ((&dio->complete_work)){+.+.}, at: [<ffffffff81083b85>] process_one_work+0x195/0x660
stack backtrace:
CPU: 16 PID: 20194 Comm: kworker/16:0 Tainted: G W 4.14.0-rc7-dbg+ #3
Hardware name: Dell Inc. PowerEdge R720/0VWT90, BIOS 1.3.6 09/11/2012
Workqueue: dio/dm-0 dio_aio_complete_work
Call Trace:
dump_stack+0x70/0x9e
print_circular_bug.isra.39+0x1d8/0x1e6
__lock_acquire+0x1248/0x1320
lock_acquire+0x95/0x1f0
down_write+0x3b/0x70
__generic_file_fsync+0x49/0xc0
ext4_sync_file+0x2ac/0x580 [ext4]
vfs_fsync_range+0x4b/0xb0
dio_complete+0x214/0x230
dio_aio_complete_work+0x1c/0x20
process_one_work+0x20a/0x660
worker_thread+0x3d/0x3b0
kthread+0x13a/0x150
ret_from_fork+0x27/0x40
