[gstreamer-bugs] [Bug 591318] New: ghostpad : core dump : on_src_target_notify called with an invalid ghostpad

[GStreamer (bugzilla.gnome.org)]

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  GStreamer | gstreamer (core) | Ver: 0.10.22
           Summary: ghostpad : core dump : on_src_target_notify called with
                    an invalid ghostpad
           Product: GStreamer
           Version: 0.10.22
          Platform: Other
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gstreamer (core)
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: gstelzz at yahoo.fr
         QAContact: gstreamer-bugs at lists.sourceforge.net
     GNOME version: Unspecified
   GNOME milestone: Unspecified


My pipeline has a tee with ghosted src request pads.

There is a race between caps notification on ghosted pads and ghost pad
release.

Pushing a buffer makes pad_push notify a caps changed on pad.
gst_pad_push -> gst_pad_configure_src -> gst_pad_set_caps ->
g_object_notify(pad, "caps") -> on_src_target_notify(pad, unused, ghostpad) 

Unlike the proxypad which has been reffed in gst_pad_push as the peer pad, the
ghost pad has not been reffed and might then be released in another thread.

This will lead to the use of an invalid pointer in on_src_target_notify.

on_src_target_notify should use the proxy pad instead of the ghost pad, and
access the ghost pad through the proxy pad, with mutex to ensure ghost pad is
valid.

I use a revision from March 2009 (something betwwen 0.10.22 and 23 I think,
with some patches), but I did not see any changes on git for this problem.


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