Exaile crashes (hangs) when reaching end of playlist

[Auria]

On Xubuntu 12.04, Exaile 0.3.2.2. When reaching the end of a playlist, Exaile hangs (stops being responsive) indefinitely.

No error message is printed on the terminal; I also tried running in in pdb but when it hanged pdb would not more break to show where it hanged

Running in gdb shows it hangs in

#0 0x00007ffff7bcb89c in __lll_lock_wait () from /lib/x86_64-linux-gnu/libpthread.so.0
#1 0x00007ffff7bc7080 in _L_lock_903 () from /lib/x86_64-linux-gnu/libpthread.so.0
#2 0x00007ffff7bc6f19 in pthread_mutex_lock () from /lib/x86_64-linux-gnu/libpthread.so.0
#3 0x00007ffff58b92e1 in g_static_rec_mutex_lock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4 0x00007fffebb8b261 in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#5 0x00007fffebb92d4d in gst_pad_activate_push () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#6 0x00007fffebb92c53 in gst_pad_activate_push () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#7 0x00007fffebb938c8 in gst_pad_set_active () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#8 0x00007fffebb60558 in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#9 0x00007fffebb854ce in gst_iterator_fold () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#10 0x00007fffebb60433 in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#11 0x00007fffebb65df7 in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#12 0x00007fffdce49373 in ?? () from /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstdecodebin2.so
#13 0x00007fffebb77dac in gst_element_change_state () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#14 0x00007fffebb786d0 in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#15 0x00007fffebb658ed in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#16 0x00007fffdce50e9a in ?? () from /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstdecodebin2.so
#17 0x00007fffebb77dac in gst_element_change_state () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#18 0x00007fffebb786d0 in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#19 0x00007fffebb658ed in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#20 0x00007fffebb972e4 in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#21 0x00007fffea4b4aab in ?? () from /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstplaybin.so
#22 0x00007fffebb77dac in gst_element_change_state () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#23 0x00007fffebb77e2f in gst_element_change_state () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#24 0x00007fffebb786d0 in ?? () from /usr/lib/x86_64-linux-gnu/libgstreamer-0.10.so.0
#25 0x00007fffec6f252d in ?? () from /usr/lib/python2.7/dist-packages/gst-0.10/gst/_gst.so
#26 0x000000000042a485 in PyEval_EvalFrameEx ()
#27 0x00000000004317f2 in PyEval_EvalCodeEx ()
#28 0x000000000054aa40 in ?? ()
#29 0x00000000004c7c76 in PyObject_Call ()
#30 0x000000000049e9ba in ?? ()

[Peter Crighton (petecrighton)]

It even cannot be closed via “killall exaile”.

[Mathias Brodala (mathbr)]

This does not happen with the latest trunk which will be released as 0.3.3. Can you give that one a try and let us know if the issue is gone?

[Dustin Spicuzza (dustin-virtualroadside)]

I installed Exaile trunk this weekend on my girlfriend's computer, and can confirm that this happens on OSX 10.4. This does not happen for me on Win32 or Kubuntu 12.04.

I haven't ran gdb on the OSX crash, but that's a good idea. From the looks of the stack, this might be a gstreamer bug?

[Dustin Spicuzza (dustin-virtualroadside)]

Note that she was playing an album of all m4a files when it hung, though I can't imagine that's related.

[Dustin Spicuzza (dustin-virtualroadside)]

So I finally got a chance to look at her machine tonight, and I figured out what the problem was. The call stack is very similar to the call stack reported by the OP.

Apparently (and I can't seem to find the documentation for this, but I found a number of forum/mailing list posts about it) you cannot do certain operations on gstreamer objects while being called by gstreamer because of an event.

On her system, the _on_about_to_finish() function in engine_normal.py was called by gstreamer, and this function called the play function, which tried to do set_state() on the pipeline object -- and this is not allowed. The reason it deadlocked was because something else had been called in a different thread, and it also was trying to set_state, thus deadlocking.

I was able to get her exaile working properly by encapsulating the _on_about_to_finish() function in a glib.idle_add(). I'll try to look tomorrow and examine the various bits of our code to see what else violates the rule, and make some fixes.

[Dustin Spicuzza (dustin-virtualroadside)]

I believe this should be fixed in r4117, when using the 'normal' playback engine. I haven't done very much testing with the unified engine yet.

[Dustin Spicuzza (dustin-virtualroadside)]

Calling this fixed, since nobody has complained yet, and OSX seems to work correctly now.

[the-unconventional (the-unconventional-deactivatedaccount-deactivatedaccount)]

Will this fixed version land in 12.04 LTS? Because it's currently still broken.

[Dustin Spicuzza (dustin-virtualroadside)]

We are not planning to backport any fixes to 0.3.2, and I imagine Ubuntu will not update Exaile to 3.3.0 in an LTS distribution. I'd recommend filing a bug against the Ubuntu package if you want them to fix it.