Bug 223695 – Metal ANGLE crashes LayoutTests/inspector/canvas/updateShader-webgl.html

• Status: RESOLVED
• Resolution: FIXED
• Component: ANGLE

[Kyle Piddington]

Metal ANGLE is crashing in this test (LayoutTests/inspector/canvas/updateShader-webgl.html), due to a bad NSDictionary. 
Switch to using allocated dictionaries, rather than stack constants.

[Kyle Piddington]

Created attachment 424141 [details]
Patch

[EWS Watchlist]

Note that there are important steps to take when updating ANGLE. See https://trac.webkit.org/wiki/UpdatingANGLE

[Alexey Proskuryakov]

Comment on attachment 424141 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=424141&action=review

> Source/ThirdParty/ANGLE/ChangeLog:4
> +Switch to using allocated dictionaries, rather than stack constants.

What is the exact mechanism for this failure? Literals are not stack constants, and should generally work everywhere.

I wonder if this is covering for an over-release somewhere with a leak.

> Source/ThirdParty/ANGLE/src/libANGLE/renderer/metal/ProgramMtl.mm:251
> -        mDefaultSubstitutionDictionary = @{@"TRANSFORM_FEEDBACK_ENABLED": @"0"};
> +        mDefaultSubstitutionDictionary = [[NSDictionary alloc] initWithDictionary:@{@"TRANSFORM_FEEDBACK_ENABLED": @"0"}];

There is a code path above that also initializes mDefaultSubstitutionDictionary with a literal. Worth updating that for consistency?

[Kenneth Russell]

I'd like to defer review to ap@ who clearly understands this code better than me, but happy to study and officially review if needed.

[Kenneth Russell]

Also: possible to add the crashing stack trace as a comment here for posterity?

[Alexey Proskuryakov]

An ASan report would likely be best for understanding what leads to the crash.

[Kyle Piddington]

Created attachment 424200 [details]
Patch

[Kyle Piddington]

Created attachment 424202 [details]
Patch

[EWS]

Committed r274990: <https://commits.webkit.org/r274990>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 424202 [details].

[Radar WebKit Bug Importer]

<rdar://problem/75815100>