536350 - WebGL shader program can freeze WindowServer

Status: RESOLVED INCOMPLETE

(Core :: Graphics: CanvasWebGL, defect)

Description

[Henri Sivonen (:hsivonen)]

Trunk; self-built on 2009-12-17.

Mac OS X 10.6.2 on a 2.4 GHz Core 2 Duo MacBook (MacBook4,1) with Intel GMA X3100 GPU; lid closed using only an external Cinema Display via DVI at 1920x1200 pixels.

Reproducible: Always.

Steps to reproduce:
 1) Enable WebGL.
 2) Load http://people.mozilla.com/~sicking/webgl/juliaanim.html
 3) If the WindowServer didn't freeze yet, click the buttons for Large, Small, etc. (My first freeze sequence was Very Large, Pause, Pause, Small. My second freeze happened immediately on session restore.)

Actual Results:
The WindowServer freezes. The mouse pointer can be moved for a while using a Wacom tablet and then the mouse pointer turns to the SBBoD and cannot be moved. Had to use the power button to reboot.

Expected results:
No freeze.

Comment 1

[Mark Steele]

Hm, I can't reproduce this with a MBP with NVIDIA graphics. This sounds like the complex shader issue.
This is, in part, a driver issue, but the real fix requires a strategy for shader validation.

Comment 2

[Henri Sivonen (:hsivonen)]

On the first viewing before clicking the buttons, I did see an animated fractal. The second time round, the freeze happened before the fractal was painted.

Comment 3

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

So, ANGLE requires much simpler loops, but the amount of work isn't necessarily going to be any less (unless the earlier loop was doing very many iterations).  This type of problem is particularly bad on the mac, where the entire OS/desktop can freeze as a result of heavy GPU usage.

Comment 4

[Kelsey Gilbert [:jgilbert]]

Broken link.