[Bug 744040] New: Deadlock when stepping

Thu Feb 5 05:19:50 PST 2015

https://bugzilla.gnome.org/show_bug.cgi?id=744040
  GStreamer | gstreamer (core) | unspecified

           Summary: Deadlock when stepping
    Classification: Platform
           Product: GStreamer
           Version: unspecified
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: Normal
         Component: gstreamer (core)
        AssignedTo: gstreamer-bugs at lists.freedesktop.org
        ReportedBy: thaytan at noraisin.net
         QAContact: gstreamer-bugs at lists.freedesktop.org
     GNOME version: ---

Encountered a locking order problem while doing some playing around in the
playback test app: A flush occuring during a step leads to a basesink deadlock.

The sink element is posting STEP_DONE, holding the STREAM_LOCK. The app sends a
new step event from the sync bus handler, which tries to take the STATE_LOCK.

Meanwhile, the app has sent a flushing seek, which is holding the STATE_LOCK,
and trying to acquire the STREAM_LOCK.

It seems either basesink should drop the stream lock while sending the
STEP_DONE message, or the app should not send the new step event from the sync
bus message handler, I'm not sure which.

Thread 13 (Thread 0x7ff135534700 (LWP 30991)):
#0  0x0000003907e0ef1d in __lll_lock_wait () at
../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
#1  0x0000003907e09906 in __GI___pthread_mutex_lock (mutex=0x1a10c00) at
../nptl/pthread_mutex_lock.c:115
#2  0x00007ff13d8a4645 in gst_element_send_event (element=0x19cb040
[GstPlayBin], event=0x7ff1280050b0) at gstelement.c:1557
#3  0x000000000040b00d in do_shuttle (app=app at entry=0x7fff95060af0) at
playback-test.c:1559
#4  0x000000000040d8c8 in msg_sync_step_done (bus=<optimized out>,
message=<optimized out>, app=0x7fff95060af0)
    at playback-test.c:1585
#5  0x00000036f6012d13 in g_cclosure_marshal_VOID__BOXEDv (closure=0x1cf0820,
return_value=<optimized out>, instance=<optimized out>, args=<optimized out>,
marshal_data=<optimized out>, n_params=<optimized out>, param_types=0x175bee0)
at gmarshal.c:1160
#6  0x00000036f600feb2 in _g_closure_invoke_va
(closure=closure at entry=0x1cf0820, return_value=return_value at entry=0x0,
instance=instance at entry=0x186a2c0, args=args at entry=0x7ff135532db0, n_params=1,
param_types=0x175bee0) at gclosure.c:831
#7  0x00000036f6029b60 in g_signal_emit_valist (instance=0x186a2c0,
signal_id=<optimized out>, detail=267, var_args=var_args at entry=0x7ff135532db0)
at gsignal.c:3218
#8  0x00000036f602a3af in g_signal_emit (instance=instance at entry=0x186a2c0,
signal_id=<optimized out>, detail=<optimized out>)
    at gsignal.c:3365
#9  0x00007ff13d88f12a in gst_bus_sync_signal_handler (bus=0x186a2c0 [GstBus],
message=0x7ff11c1702c0, data=<optimized out>)
    at gstbus.c:1197
#10 0x00007ff13d88f3c4 in gst_bus_post (bus=bus at entry=0x186a2c0 [GstBus],
message=message at entry=0x7ff11c1702c0) at gstbus.c:329
#11 0x00007ff13d8a1bf8 in gst_element_post_message_default
(element=element at entry=0x19cb040 [GstPlayBin], message=0x7ff11c1702c0)
    at gstelement.c:1688
#12 0x00007ff13d883c4f in gst_bin_post_message (element=0x19cb040 [GstPlayBin],
msg=0x7ff11c1702c0) at gstbin.c:2523
#13 0x00007ff13d883f79 in gst_bin_handle_message_func (bin=0x19cb040
[GstPlayBin], message=<optimized out>) at gstbin.c:3745
#14 0x00007ff13d8c4939 in gst_pipeline_handle_message (bin=0x19cb040
[GstPlayBin], message=0x7ff11c1702c0) at gstpipeline.c:574
#15 0x00007ff136247ca5 in gst_play_bin_handle_message (bin=0x19cb040
[GstPlayBin], msg=0x7ff11c1702c0) at gstplaybin2.c:2912
#16 0x00007ff13d880828 in bin_bus_handler (bus=bus at entry=0x186a1f0 [GstBus],
message=message at entry=0x7ff11c1702c0, bin=bin at entry=0x19cb040 [GstPlayBin]) at
gstbin.c:2981
#17 0x00007ff13d88f39b in gst_bus_post (bus=bus at entry=0x186a1f0 [GstBus],
message=message at entry=0x7ff11c1702c0) at gstbus.c:323
#18 0x00007ff13d8a1bf8 in gst_element_post_message_default
(element=element at entry=0x1b06020 [GstPlaySink], message=0x7ff11c1702c0)
    at gstelement.c:1688
#19 0x00007ff13d883c4f in gst_bin_post_message (element=0x1b06020
[GstPlaySink], msg=0x7ff11c1702c0) at gstbin.c:2523
---Type <return> to continue, or q <return> to quit---
#20 0x00007ff13d883f79 in gst_bin_handle_message_func (bin=0x1b06020
[GstPlaySink], message=<optimized out>) at gstbin.c:3745
#21 0x00007ff13624ce30 in gst_play_sink_handle_message (bin=0x1b06020
[GstPlaySink], message=0x7ff11c1702c0) at gstplaysink.c:4632
#22 0x00007ff13d880828 in bin_bus_handler (bus=bus at entry=0x186a390 [GstBus],
message=message at entry=0x7ff11c1702c0, bin=bin at entry=0x1b06020 [GstPlaySink]) at
gstbin.c:2981
#23 0x00007ff13d88f39b in gst_bus_post (bus=bus at entry=0x186a390 [GstBus],
message=message at entry=0x7ff11c1702c0) at gstbus.c:323
#24 0x00007ff13d8a1bf8 in gst_element_post_message_default
(element=element at entry=0x7ff12000f790 [GstBin], message=0x7ff11c1702c0)
    at gstelement.c:1688
#25 0x00007ff13d883c4f in gst_bin_post_message (element=0x7ff12000f790
[GstBin], msg=0x7ff11c1702c0) at gstbin.c:2523
#26 0x00007ff13d883f79 in gst_bin_handle_message_func (bin=0x7ff12000f790
[GstBin], message=<optimized out>) at gstbin.c:3745
#27 0x00007ff13d880828 in bin_bus_handler (bus=bus at entry=0x7ff120010230
[GstBus], message=message at entry=0x7ff11c1702c0, bin=bin at entry=0x7ff12000f790
[GstBin]) at gstbin.c:2981
#28 0x00007ff13d88f39b in gst_bus_post (bus=bus at entry=0x7ff120010230 [GstBus],
message=message at entry=0x7ff11c1702c0) at gstbus.c:323
#29 0x00007ff13d8a1bf8 in gst_element_post_message_default
(element=0x7ff124049a10 [GstXvImageSink], message=0x7ff11c1702c0)
    at gstelement.c:1688
#30 0x00007ff13de482d7 in stop_stepping (sink=sink at entry=0x7ff124049a10
[GstXvImageSink], segment=segment at entry=0x7ff124049b68,
current=current at entry=0x7ff124049918, rstart=<optimized out>,
rstop=16605853000, eos=0) at gstbasesink.c:1694
#31 0x00007ff13de52def in gst_base_sink_chain_unlocked
(basesink=basesink at entry=0x7ff124049a10 [GstXvImageSink],
obj=obj at entry=0x7ff11c3541c0, is_list=is_list at entry=0, pad=<optimized out>) at
gstbasesink.c:3457
#32 0x00007ff13de544a4 in gst_base_sink_chain_main (basesink=0x7ff124049a10
[GstXvImageSink], pad=<optimized out>, obj=0x7ff11c3541c0, is_list=0) at
gstbasesink.c:3547
#33 0x00007ff13d8ba704 in gst_pad_push_data (data=0x7ff11c3541c0, type=4112,
pad=0x7ff124040340 [GstPad]) at gstpad.c:3838

Thread 1 (Thread 0x7ff13d832980 (LWP 30975)):
#0  0x0000003907e0ef1d in __lll_lock_wait () at
../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
#1  0x0000003907e09906 in __GI___pthread_mutex_lock (mutex=0x7ff124048ce0) at
../nptl/pthread_mutex_lock.c:115
#2  0x00007ff13de4bc52 in gst_base_sink_flush_start
(basesink=basesink at entry=0x7ff124049a10 [GstXvImageSink], pad=0x7ff124040340
[GstPad]) at gstbasesink.c:2910
#3  0x00007ff13de4c1c1 in gst_base_sink_default_event (basesink=0x7ff124049a10
[GstXvImageSink], event=0x7ff12009f020)
    at gstbasesink.c:3001
#4  0x00007ff134281ac7 in gst_xvimagesink_event (sink=0x7ff124049a10
[GstXvImageSink], event=0x7ff12009f020) at xvimagesink.c:1036
#5  0x00007ff13d8b8ff8 in gst_pad_send_event_unchecked
(pad=pad at entry=0x7ff124040340 [GstPad], event=event at entry=0x7ff12009f020,
type=type at entry=320) at gstpad.c:5157
#6  0x00007ff13d8b96cf in gst_pad_push_event_unchecked (pad=pad at entry=0x1d4b600
[GstGhostPad], event=event at entry=0x7ff12009f020, type=320,
type at entry=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at gstpad.c:4844
#7  0x00007ff13d8c24a4 in gst_pad_push_event (pad=pad at entry=0x1d4b600
[GstGhostPad], event=0x7ff12009f020) at gstpad.c:4975
#8  0x00007ff13d8c27f3 in event_forward_func (pad=pad at entry=0x1d4b600
[GstGhostPad], data=data at entry=0x7fff95059880) at gstpad.c:2849
#9  0x00007ff13d8bf5ae in gst_pad_forward (pad=pad at entry=0x7ff12801d930
[GstProxyPad], forward=forward at entry=0x7ff13d8c2730 <event_forward_func>,
user_data=user_data at entry=0x7fff95059880) at gstpad.c:2803
#10 0x00007ff13d8bf6db in gst_pad_event_default (pad=pad at entry=0x7ff12801d930
[GstProxyPad], parent=parent at entry=0x1d4b600 [GstGhostPad],
event=event at entry=0x7ff12009f020) at gstpad.c:2900
#11 0x00007ff13d8b8ff8 in gst_pad_send_event_unchecked
(pad=pad at entry=0x7ff12801d930 [GstProxyPad], event=event at entry=0x7ff12009f020,
type=type at entry=320) at gstpad.c:5157
#12 0x00007ff13d8b96cf in gst_pad_push_event_unchecked
(pad=pad at entry=0x7ff1200a36d0 [GstPad], event=event at entry=0x7ff12009f020,
type=320, type at entry=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at gstpad.c:4844
#13 0x00007ff13d8c24a4 in gst_pad_push_event (pad=0x7ff1200a36d0 [GstPad],
event=event at entry=0x7ff12009f020) at gstpad.c:4975
#14 0x00007ff13de628a6 in gst_base_transform_sink_eventfunc
(trans=0x7ff11c15c4d0 [GstVideoConvert], event=0x7ff12009f020)
    at gstbasetransform.c:1923

-- 
Configure bugmail: https://bugzilla.gnome.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.
You are the assignee for the bug.