[Mesa-dev] [Bug 108996] Leaks buffer when closing wayland window

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108996

Bug ID: 108996
Summary: Leaks buffer when closing wayland window
Product: Mesa
Version: git
Hardware: Other
OS: All
Status: NEW
Severity: normal
Priority: medium
Component: EGL/Wayland
Assignee: wayland-***@lists.freedesktop.org
Reporter: ***@luon.net
QA Contact: mesa-***@lists.freedesktop.org

Hey,

When closing a EGL using window on wayland it seems there is always a (color)
buffer leaked until the process exits; We first noticed this with Qt using apps
on an etnaviv based system, however the same can be reproduce on Intel gpu's

To reproduce I created a modified weston-simple-egl[0] which simply every 60
frames will destroy the current surface and create a new one[1].

As mentioned the issue both occurs on both etnaviv and intel systems where
there is seemingly one dmabuf leaked every time the window gets closed (as per
/sys/kernel/debug/dma_buf/bufinfo). It can also be reproduce by using software
rendering (LIBGL_ALWAYS_SOFTWARE=1) in which case memory grows every time the
window is recreated (presumably for the same reason).

While tracing it down as far as i could it seems that the `current` buffer of
the relevant dri2_egl_surface has extra references on it when ->destroyImage
gets called on match color_buffer in `dri2_wl_destroy_surface` (while the other
allocated buffers/driImages don't). Why these extra references (presumably for
the next render?) aren't cleared up is unfortunately a bit beyond my
understanding of mesa.

This is reproducable both with mesa 18.2.6 and git master


[0] https://gitlab.freedesktop.org/sjoerd/weston/tree/mesa-leak
[1]
https://gitlab.freedesktop.org/sjoerd/weston/commit/934e195c1b4d5fdd7ec006c8f7048ad30df8738f