1305151 - Allow disabling of Skia asserts in debug builds

Status: RESOLVED FIXED

(Core :: Graphics, defect, P3)

Description

[Lee Salzman [:lsalzman]]

Attachment: allow disabling Skia debug assertions via MOZ_SKIA_DISABLE_ASSERTS env-var

It is very easy to trip up Skia debug asserts by stressing numerical precision. Skia extensively uses single-precision floats throughout, and debug code is similarly scattered about that will usually fail when this precision is stressed because it only expects to be provided with sane use-cases (i.e. ones that are actually renderable). The consequences of most of these asserts failing is simply that things will fail to render, or maybe just look a little bit off.

This Skia debug code is antagonistic with our fuzzer efforts, since the fuzzers will often trip up in Skia, when what we really want to catch is bugs in our own code, or crashes that occur under our normal test infrastructure.

One possible way to resolve this antagonism is to give the fuzzer a way to disable Skia's assertions at runtime. We could do this via an env-var such as MOZ_SKIA_DISABLE_ASSERTS which the fuzzer can supply. This would not affect our normal test infrastructure or releases since it would not be defined there.

Comment 1

[Milan Sreckovic [:milan] (needinfo for best results)]

Comment on attachment 8794400 [details] [diff] [review]
allow disabling Skia debug assertions via MOZ_SKIA_DISABLE_ASSERTS env-var

Review of attachment 8794400 [details] [diff] [review]:
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I can live with this.

Comment 2

[Tyson Smith [:tsmith]]

Should I continue to log the skia assertions as they come up? They aren't really getting in the way at the moment. That said they may be a pain to fix on the dev side.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/2c645653db8c
allow disabling Skia debug assertions via MOZ_SKIA_DISABLE_ASSERTS env-var. r=milan

Comment 4

[Lee Salzman [:lsalzman]]

(In reply to Tyson Smith [:tsmith] from comment #2)
> Should I continue to log the skia assertions as they come up? They aren't
> really getting in the way at the moment. That said they may be a pain to fix
> on the dev side.

Whatever you already found/filed, just do as usual. For new ones, I recommend you define MOZ_SKIA_DISABLE_ASSERTS=1 in the env so that it will only catch actual crashes in Skia from now on.

Comment 5

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/2c645653db8c