Bug 51535 - Disposing Pixbuf leaks memory
Summary: Disposing Pixbuf leaks memory
Alias: None
Product: Gtk#
Classification: Mono
Component: gtk-sharp ()
Version: 2.x
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Marius Ungureanu
Depends on:
Reported: 2017-01-14 12:35 UTC by dk
Modified: 2017-05-23 18:45 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

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Description dk 2017-01-14 12:35:34 UTC
Disposing a Pixbuf does not free the unmanaged memory used by it.

Observed on Arch Linux using:

  mono runtime:
  gtk-sharp:    2.12.42 (https://www.archlinux.org/packages/extra/x86_64/gtk-sharp-2/)

If I downgrade to gtk-sharp version 2.12.29 the issue is gone (this is the previous version provided by Arch Linux before it was upgraded to 2.12.42).

Sample to reproduce (memory usage is constantly increasing instead of staying at the same level as expected):

static int Main (string [] args)
    System.Diagnostics.Process currentProcess = System.Diagnostics.Process.GetCurrentProcess();

    for (int i = 0; i < 30; i++) {
        long totalBytesOfMemoryUsed = currentProcess.WorkingSet64;
        System.Console.WriteLine ("Memory: " + totalBytesOfMemoryUsed / 1024 / 1024 + " MB");
        using (var stream = new GLib.GioStream (GLib.FileFactory.NewForUri ("file:///path/to/image.jpg").Read (null))) {
            Gdk.Pixbuf p;
            using (var loader = new Gdk.PixbufLoader (stream)) {
                p = loader.Pixbuf;
                loader.Close ();
            p.Dispose ();
            p = null;
    return 0;
Comment 1 Marius Ungureanu 2017-05-23 18:44:49 UTC
Since there is no glib main loop, dispose needs to be called. I have a patch to fix this, we were improperly refing the pixbuf (managed wrapper takes a ref, we don't need to ref more).

Here's the pull request for it - https://github.com/mono/gtk-sharp/pull/188
Comment 2 Marius Ungureanu 2017-05-23 18:45:02 UTC
Thank you for the bug report, helped me diagnose this easily.