Subject: bug#58334: 29.0.50; ASAN heap use after free in gui_produce_glyphs

From: Gerd Möllmann <[email-masked]>
Date: Fri, 07 Oct 2022 10:54:34 +0200

Po Lu <[email-masked]> writes:

> Gerd Möllmann <[email-masked]> writes:
>
>> And, while vaccuming, I also wondered what happens with the glyph
>> matrices, and maybe other global state?
>
> Isn't input blocked wherever the glyph matrices are modified?
> If not,

Partly.  Eli please correct me if this has changed.

Redisplay has two phases:

1. Building desired matrices, that is, what should be on the screen
after redisplay.

2. Updating current matrices from desired matrices, and bringing that on
the screen.

Only phase 2 has input blocked because the current matrices are
modified, which are shared state with the GUI code.

> how come expose_frame always works correctly?

Expose uses only current matrices.