947847 - frequent warnings about empty rectangle with nsRegion::Copy(const nsRect&) on --enable-system-cairo

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Jan Beich]

When building against vanilla cairo-1.10.2 or cairo-1.12.16 firefox shows the following messages to stderr. This doesn't happen with just --enable-system-pixman.

$ firefox -P test -no-remote www.mozilla.org

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffffa550, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 0,
          y1 = 0,
          x2 = 0,
          y2 = 0
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff7578, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 480,
          y1 = 0,
          x2 = 480,
          y2 = 960
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff9d08, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 0,
          y1 = 5640,
          x2 = 0,
          y2 = 5640
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff9d08, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 0,
          y1 = 5640,
          x2 = 0,
          y2 = 5640
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff9d08, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 0,
          y1 = 5640,
          x2 = 0,
          y2 = 5640
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff8e48, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 480,
          y1 = 0,
          x2 = 480,
          y2 = 960
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff9d08, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 0,
          y1 = 5640,
          x2 = 0,
          y2 = 5640
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff9d08, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 28362,
          y1 = 19722,
          x2 = 28362,
          y2 = 19722
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff9d08, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 28362,
          y1 = 19722,
          x2 = 28362,
          y2 = 19722
        }

*** BUG ***
In void pixman_region32_reset(region_type_t *, box_type_t *): The expression GOOD_RECT (box) was false
Set a breakpoint on '_pixman_log_error' to debug

#2  0x00000008047c83b6 in nsRegion::Copy (this=0x7fffffff9d08, aRect=...) at gfx/src/nsRegion.h:260
        box = {
          x1 = 28362,
          y1 = 19722,
          x2 = 28362,
          y2 = 19722
        }

etc...

Comment 1

[Jeff Muizelaar [:jrmuizel]]

Can you get a backtrace from the point when this happens?

Comment 2

[Jan Beich]

Attachment: one

Attaching 5 backtraces in hope you can see the pattern.

Comment 3

[Jan Beich]

Attachment: two

Comment 4

[Jan Beich]

Attachment: three

Comment 5

[Jan Beich]

Attachment: four

Comment 6

[Jan Beich]

Attachment: five

Comment 7

[Jeff Muizelaar [:jrmuizel]]

Attachment: Avoid reseting to empty rects

pixman_region32_reset will give an error if the rectangle you pass to it is empty. We can just check before hand if the rect is empty and in that case just call pixman_region32_clear instead of pixman_region32_reset.

Comment 8

[Jan Beich]

Confirming, with the above patch no BUG messages are printed to stderr. The landing link Jeff forgot is

https://hg.mozilla.org/integration/mozilla-inbound/rev/982d8e522f18

Comment 9

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/982d8e522f18

Comment 10

[Mike Conley (:mconley) (:⚙️)]

This patch is conflicting when we attempt to merge mozilla-central into holly.

Can it be backed out of Holly, or can an alternative patch for Holly be generated?

Comment 11

[Jeff Muizelaar [:jrmuizel]]

(In reply to Mike Conley (:mconley) from comment #10)
> This patch is conflicting when we attempt to merge mozilla-central into
> holly.
> 
> Can it be backed out of Holly, or can an alternative patch for Holly be
> generated?

This patch can be dropped completely from Holly

Comment 12

[Mike Conley (:mconley) (:⚙️)]

This was backed out from Holly as:

https://hg.mozilla.org/projects/holly/rev/6638a0ea1d44