[Pixman] [PATCH] Fix server crash in pixman (to be discussed)

[Jonathan Morton]

On Wed, 2010-03-24 at 12:22 +0100, Matthias Hopf wrote:
> Reading the source in render/glyph.c in the Xserver it seems that the
> glyph to be rendered is empty (glyph->info.width=glyph->info.height=0).
> Question is now whether that is allowed or not.
> 
> If it is question remains on which level this should be fixed. If it
> is not, question remains why this could happen.

AFAIK, space glyphs are usually empty.

Drawing a string containing spaces but also other characters would
result in a non-degenerate region, presumably.  So the bug might be
triggered by a string containing only a space.

It may be appropriate to use a "belt and braces" approach here - prevent
the degenerate regions from being created, *and* have the PIXREGION_NIL
macro handle them.

-- 
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From: Jonathan Morton
      jonathan.morton at movial.com