Crashes on gst_bus_add_watch

Sun Feb 3 10:21:47 PST 2013

Honestly I'm not very sure about the real cause. I think it might have
failed to request some resources. I added many locks for many situation (my
latest code is at https://github.com/duzy/gst-switch), and changed a method
of log messages, refactored my code a lot, and *gst_bus_create_watch* issue
seems gone. But I'm now confronting another issue, complaining:

(gst-switch-srv:1709): GLib-ERROR **: *Creating pipes for GWakeup: Too many
open files*

This is happened almost 100% percent, by running the a test for nearly 2
minutes. And this test was trying to make request to
*gst-switch-srv*indirectly to recreate the pipelines repeatedly and
very fast (I spawned
three threads in the test for making the requests to the server, and it
will at least recreate three pipelines in a request).

Everything looks fine, except for the *too-many-open-files* error. And this
time my stack looks like this (the latest changes):

*bt*
#0  *g_logv* (log_domain=0x7ffff72d11ae "GLib",
log_level=G_LOG_LEVEL_ERROR, format=<optimized out>,
args=args at entry=0x7fffffffddb8)
at /build/buildd/glib2.0-2.34.1/./glib/gmessages.c:974
#1  0x00007ffff7297e42 in *g_log* (log_domain=log_domain at entry=0x7ffff72d11ae
"GLib", log_level=log_level at entry=G_LOG_LEVEL_ERROR,
format=format at entry=0x7ffff7323030
"Creating pipes for GWakeup: %s\n") at
/build/buildd/glib2.0-2.34.1/./glib/gmessages.c:1003
#2  0x00007ffff72cd113 in *g_wakeup_new* () at
/build/buildd/glib2.0-2.34.1/./glib/gwakeup.c:163
#3  0x00007ffff728ed47 in *g_main_context_new* () at
/build/buildd/glib2.0-2.34.1/./glib/gmain.c:590
#4  0x00007fffd1cb1071 in
*gst_multi_socket_sink_start_pre*(mhsink=0x23564d0) at
gstmultisocketsink.c:1005
#5  0x00007fffd1cacc50 in *gst_multi_handle_sink_start* (bsink=0x23564d0)
at gstmultihandlesink.c:2112
#6  *gst_multi_handle_sink_change_state* (element=0x23564d0,
transition=<optimized out>) at gstmultihandlesink.c:2205
#7  0x00007ffff7b2e28c in *gst_element_change_state*
(element=element at entry=0x23564d0,
transition=<optimized out>) at gstelement.c:2594
#8  0x00007ffff7b2ec61 in *gst_element_set_state_func* (element=0x23564d0,
state=GST_STATE_READY) at gstelement.c:2550
#9  0x00007ffff7b16579 in
*gst_bin_element_set_state*(next=GST_STATE_READY,
current=GST_STATE_NULL, start_time=0, base_time=0,
element=0x23564d0, bin=0x217f1b0) at gstbin.c:2308
#10 *gst_bin_change_state_func* (element=0x217f1b0,
transition=GST_STATE_CHANGE_NULL_TO_READY) at gstbin.c:2610
#11 0x00007ffff7b2e28c in *gst_element_change_state*
(element=element at entry=0x217f1b0,
transition=<optimized out>) at gstelement.c:2594
#12 0x00007ffff7b2ec61 in *gst_element_set_state_func* (element=0x217f1b0,
state=GST_STATE_READY) at gstelement.c:2550
#13 0x0000000000405961 in *gst_worker_start* (worker=0x62f0f0) at
gstworker.c:236
#14 0x000000000040bc30 in
*gst_composite_close_transition*(composite=0x706800) at
gstcomposite.c:513
#15 *gst_composite_alive* (composite=0x706800) at gstcomposite.c:565
#16 0x00000000004063ca in
*gst_worker_state_paused_to_playing*(worker=0x706800) at
gstworker.c:412
#17 *gst_worker_pipeline_state_changed* (statechange=<optimized out>,
worker=0x706800) at gstworker.c:463
#18 *gst_worker_message* (bus=<optimized out>, message=0x7fffd80138a0,
worker=0x706800) at gstworker.c:542
#19 0x00007ffff7b1dc67 in *gst_bus_source_dispatch*
(source=source at entry=0x23614f0,
callback=0x405b40 <gst_worker_message>, user_data=0x706800) at gstbus.c:773
#20 0x00007ffff7290ab5 in *g_main_dispatch* (context=0x61f2d0) at
/build/buildd/glib2.0-2.34.1/./glib/gmain.c:2715
#21 *g_main_context_dispatch* (context=context at entry=0x61f2d0) at
/build/buildd/glib2.0-2.34.1/./glib/gmain.c:3219
#22 0x00007ffff7290de8 in *g_main_context_iterate* (context=0x61f2d0,
block=block at entry=1, dispatch=dispatch at entry=1, self=<optimized out>) at
/build/buildd/glib2.0-2.34.1/./glib/gmain.c:3290
#23 0x00007ffff72911e2 in *g_main_loop_run* (loop=0x706760) at
/build/buildd/glib2.0-2.34.1/./glib/gmain.c:3484
#24 0x00000000004044c0 in *gst_switch_server_run* (srv=0x708000) at
gstswitchserver.c:1095
#25 *main* (argc=1, argv=0x7fffffffe578) at gstswitchserver.c:1119

The top several call frames are almost 100% percent path. And the key
location of my client code is at:

https://github.com/duzy/gst-switch/blob/switch/tools/gstworker.c#L681

Which is doing recreation of three pipelines. I've been tracking on it for
some days, but not yet have found the exact cause point. But I'm very sure
that those leaked file descriptors are all of "unix socket" class, and
should be created by *g_unix_open_pipe*. E.g. those already opened files
(part, total 1024):

....
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 750 -> socket:[2418126]
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 751 -> socket:[2418138]
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 752 -> socket:[2418139]
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 753 -> socket:[2418140]
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 754 -> socket:[2417418]
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 755 -> socket:[2417357]
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 756 -> socket:[2417358]
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 757 -> socket:[2415573]
  lrwx------ 1 duzy duzy 64 Feb  4 01:46 758 -> socket:[2415574]
....

I'm now think that if my previous issue was actually not solved, and that's
actually very much related to too-many-open-files issue. Say:

GStreamer-CRITICAL **: gst_poll_get_read_gpollfd: assertion `set != NULL'
failed
GStreamer-CRITICAL **: gst_bus_create_watch: assertion `bus->priv->poll !=
NULL' failed
GLib-CRITICAL **: g_source_set_callback: assertion `source != NULL' failed

Hope you would have some ideas.

Best Regards
Duzy Chan

On Sat, Jan 26, 2013 at 7:50 PM, Tim-Philipp Müller <t.i.m at zen.co.uk> wrote:

> On Sat, 2013-01-26 at 08:08 +0800, Duzy Chan wrote:
>
> > Problem solved. Thanks all.
>
> So what was the problem/solution? Something in your code?
>
>  Cheers
>   -Tim
>
>
>
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