Bug#1077800: mutter: flaky test basic-x11: In pixman_region32_init_rect: Invalid rectangle passed; cogl_texture_2d_new_from_data: assertion 'data != NULL' failed

[Simon McVittie]

Source: mutter
Version: 46.3.1-7
Severity: important
Tags: ftbfs
User: debian-ci at lists.debian.org
Usertags: flaky

The build-time tests for mutter 46.3.1-7 failed once on amd64, and three
times on ppc64el, before succeeding after a bunch of retries. This bug
report is about the failure that was seen on amd64, which was also seen
(among others) in two of the three ppc64el failures. Please consider other
failures to be out-of-scope here unless there is evidence that they share
a root cause.

Part of the test log from amd64:

> # 1..1
> # libmutter-MESSAGE: Added virtual monitor Meta-0
> # mutter-test-runner-DEBUG: basic-x11.metatest:1: 'new_client 1 x11'
> Xwayland glamor: GBM Wayland interfaces not available
> Failed to initialize glamor, falling back to sw
> # mutter-test-runner-DEBUG: basic-x11.metatest:2: 'create 1/1'
> MESA: error: ZINK: vkCreateInstance failed (VK_ERROR_INCOMPATIBLE_DRIVER)
> libEGL warning: egl: failed to create dri2 screen
> # mutter-test-runner-DEBUG: basic-x11.metatest:3: 'show 1/1'
> # mutter-test-runner-DEBUG: basic-x11.metatest:4: 'create 1/2'
> # mutter-test-runner-DEBUG: basic-x11.metatest:5: 'show 1/2'
> *** BUG ***
> In pixman_region32_init_rect: Invalid rectangle passed
> Set a breakpoint on '_pixman_log_error' to debug
> 
> *** BUG ***
> In pixman_region32_init_rect: Invalid rectangle passed
> Set a breakpoint on '_pixman_log_error' to debug
> 
> Bail out! FATAL-CRITICAL: cogl_texture_2d_new_from_data: assertion 'data != NULL' failed

The reason for failure is the cogl_texture_2d_new_from_data assertion
failure (something passed an invalid argument to that function), but the
pixman assertion failures are probably related.

I imagine that this must be timing-related, and it will probably also
happen intermittently in autopkgtests (I think we run essentially the same
set of tests in both places).

    smcv