Gstreamer & GLib memory management/profiling

[Olivier Crête]

Hi,

If you attach GDB, you'll see that this is actually a GLib bug. The
g_signal_nodes table is allocated from the ctor, so before your main is
called. Then when it tries to re-alloc that with the profiler, it fail.
The g_mem_set_vtable() is actually incompatible with GObject itself...

Olivier

On 31/10/14 11:42 AM, Sergei Vorobyov wrote:
> I "forgot" the line
> 
> extern GMemVTable *glib_mem_profiler_table;
> 
> before int main ....
> 
> (by a nasty habit of C-x C-s, which saves in emacs but kills the line
> and saves in Netbeans)
> 
> But it *does not change anything*, since it is already defined somewhere
> in GLib headers.
> 
> 
> 
> On Fri, Oct 31, 2014 at 4:34 PM, Sergei Vorobyov
> <sergei.vorobyov at facilitylabs.com
> <mailto:sergei.vorobyov at facilitylabs.com>> wrote:
> 
>     > I don't see why anything in GStreamer should be "incompatible" with that
>     > GLib API.
> 
>     Neither do I. However, try a *FULL* program below:
> 
>     // Compile with:
>     // gcc -std=c11 -Wall -pthread test.c -o test `pkg-config --cflags
>     --libs glib-2.0 gstreamer-1.0 gstreamer-pbutils-1.0 gstreamer-video-1.0`
>     // Run and enjoy
> 
>     #include <stdio.h>
>     #include <stdlib.h>
> 
>     #include <string.h>
>     #include <unistd.h>
>     #include <error.h>
>     #include <errno.h>
>     #include <math.h>
> 
>     #include <glib.h>
>     #include <glib/gstdio.h>
>     #include <glib/gprintf.h>
> 
>     #include <gst/gst.h>
>     #include <gst/pbutils/pbutils.h>
>     #include <gst/video/videooverlay.h>
> 
>     int main(int argc, char** argv) {
>         GError *e;
>         g_mem_set_vtable (glib_mem_profiler_table);
>         if (g_mem_is_system_malloc ())
>             g_print ("system malloc is used\n");
>         else
>             g_print ("NOT system malloc is used\n");
>         g_print ("********************* point 1\n");
>         if (!gst_init_check (&argc, &argv, &e))
>             g_print ("failed gst_init_check: %s\n", e->message);
>         g_print ("********************* point 2\n");
>         g_mem_profile ();
>         return (EXIT_SUCCESS);
>     }
> 
>     It produces, as expected:
> 
>     fl at nuc5:~/NetBeansProjects/test$ ./test 
>     NOT system malloc is used
>     ********************* point 1
> 
>     (test:3987): GLib-WARNING **: free(0x1a84fd0): memory has been freed
>     12297829382473034410 times already
>     *** Error in `./test': realloc(): invalid pointer:
>     0x0000000001a87e80 ***
>     Aborted (core dumped)
> 
> 
>     On Fri, Oct 31, 2014 at 2:20 PM, Tim Müller <tim at centricular.com
>     <mailto:tim at centricular.com>> wrote:
> 
>         On Fri, 2014-10-31 at 13:46 +0100, Sergei Vorobyov wrote:
> 
>         Hi,
> 
>         > GLib's memory profiling seems incompatible with GStreamer. The
>         > snippet:
> 
>         I don't see why anything in GStreamer should be "incompatible"
>         with that
>         GLib API.
> 
>         > extern GMemVTable *glib_mem_profiler_table;
>         >
>         >
>         > gint main (gint argn, gchar** args) {
>         >     GError *e;
>         >     g_mem_set_vtable (glib_mem_profiler_table);
>         >     if (g_mem_is_system_malloc ())
>         >         g_print ("system malloc is used\n");
>         >     else
>         >         g_print ("NOT system malloc is used\n");
>         >     g_print ("********************* point 1\n");
>         >     if (!gst_init_check (&argn, &args, &e)) {
>         >         g_print ("failed gst_init_check: %s\n", e->message);
>         >     }
>         >     g_print ("********************* point 2\n");
>         >
>         >     g_mem_profile ();
>         >
>         >
>         >     ...
>         >
>         >
>         > crashes at gst_init producing:
>         >
>         >
>         > fl at nuc5:~/bin$ ./mp-v01.020
>         > NOT system malloc is used
>         > ********************* point 1
>         >
>         >
>         > (mp-v01.020:15561): GLib-WARNING **: free(0x1b32fd0): memory has been
>         > freed 12297829382473034410 times already
>         > *** Error in `./mp-v01.020': realloc(): invalid pointer:
>         > 0x0000000001b35e80 ***
>         > Aborted (core dumped)
> 
>         I would guess this is just a bug somewhere (mixing glib and non-glib
>         alloc/realloc/free API somewhere). Do you have a full stack
>         trace from
>         gdb?
> 
>         Cheers
>          -Tim
> 
> 
>         _______________________________________________
>         gstreamer-devel mailing list
>         gstreamer-devel at lists.freedesktop.org
>         <mailto:gstreamer-devel at lists.freedesktop.org>
>         http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> 
> 
> 
> 
> 
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> 

-- 
Olivier Crête
olivier.crete at collabora.com