Hello @garetxe

I've come across an odd memory issue with haskell-gi-base for versions >= 0.20.5.

The latest version that works is haskell-gi-base == 0.20.4.

Based on the change log, in version 0.20.5, it looks as though there was some work done regarding freeing memory.

To demonstrate the issue, I've carved up Move Monad into a minimal example.

Here is the crash log. Here is the output from GDB.

From what I can tell, the issue occurs when a GstMessage (Hackage Link) is freed.

Freeing a boxed object at 0x3157ba0 from idle callback [thread: 0x7fffc0008490]
	It is of type GstMessageClockLost

(movie-monad:18421): GLib-GObject-CRITICAL **: g_boxed_free: assertion 'G_TYPE_IS_BOXED (boxed_type)' failed

I believe part of the stack trace is the following.

https://github.com/haskell-gi/haskell-gi/blob/master/base/Data/GI/Base/ManagedPtr.hs#L296
https://github.com/haskell-gi/haskell-gi/blob/master/base/Data/GI/Base/ManagedPtr.hs#L299
https://github.com/haskell-gi/haskell-gi/blob/master/base/Data/GI/Base/ManagedPtr.hs#L279
https://github.com/haskell-gi/haskell-gi/blob/master/base/c/hsgclosure.c#L66
https://github.com/haskell-gi/haskell-gi/blob/master/base/c/hsgclosure.c#L57
https://github.com/GNOME/glib/blob/glib-2-0/gobject/gboxed.c#L394
https://github.com/GNOME/glib/blob/glib-2-0/gobject/gtype.c#L2589
https://github.com/GNOME/glib/blob/glib-2-0/gobject/gboxed.c#L394

Given this, GType gtype is not a boxed type.

From the debug information we know the GType is GstMessageClockLost but I cannot find any documentation about this GType and if it is a boxed type. From what I can find it is a GQuark string. I'm not too familiar with g_type_name but I would think that the GType would be GstMessage which is a boxed type based on the documentation page.

Looking at the GStreamer code, the GIR, and the generated code.

https://github.com/GStreamer/gstreamer/blob/master/gst/gstmessage.h#L188
https://github.com/GStreamer/gstreamer/blob/master/gst/gstmessage.h#L190
https://github.com/GStreamer/gstreamer/blob/master/gst/gstmessage.h#L346
https://github.com/GStreamer/gstreamer/blob/master/gst/gstmessage.c#L119
https://github.com/GStreamer/gstreamer/blob/master/gst/gstminiobject.h#L291
https://github.com/GStreamer/gstreamer/blob/master/gst/gstmessage.c#L120
https://github.com/GStreamer/gstreamer/blob/master/gst/gstmessage.c#L135

So it looks as though they programmatically define boxed GTypes based on the GQuark strings/names and provide an interface to the GType of the GstMessage via its GstMiniObject member.

    <record name="Message"
            c:type="GstMessage"
            glib:type-name="GstMessage"
            glib:get-type="gst_message_get_type"
            c:symbol-prefix="message">

instance BoxedObject Message where
    boxedType _ = c_gst_message_get_type

Curiously, I've only come across this issue on Debian based systems (except for one). The three Arch based systems and the single Fedora system I tested do not have the issue.

Affected Systems

• Deepin 15.4.1
  • GStreamer 1.12.1
  • GTK+3 3.22.17
  • Kernel 4.9.0
• Ubuntu 16.04
  • GStreamer 1.8.3
  • GTK+3 3.20.8
  • Kernel 4.9.31
• Linux Mint 18
  • GStreamer 1.8.0
  • GTK+3 3.18.9
  • Kernel 4.4.0
• Ubuntu 14.04
  • GStreamer 1.6.3
  • GTK+3 3.10.8
  • Kernel 4.4.0

Unaffected Systems

• Ubuntu 17.10
  • GStreamer 1.12.3
  • GTK+3 3.22.25
  • Kernel 4.13.0
• Manjaro 17.0.2
  • GStreamer 1.12.2
  • GTK+3 3.22.16
  • Kernel 4.9.39
• Manjaro 17.0.5
  • GStreamer 1.12.2
  • GTK+3 3.22.21
  • Kernel 4.9.50
• Arch Rolling
  • GStreamer 1.12.0
  • GTK+3 3.22.16
  • Kernel 4.13.9
• Fedora 27
  • GStreamer 1.12.3
  • GTK+3 3.22.24
  • Kernel 4.13.9

I tried different versions of GTK+3 and GStreamer (even using the unreleased GStreamer 1.13.0 version) but the only consistent change that reproduced the issue was moving haskell-gi-base from version 0.20.4 to 0.20.{5,6,7}.

This is what the minimal example looks like if it works.

Note that you'll need the GStreamer 1.0 base, good, and bad plugins to run the example.

👍