Bug 42978

Summary:

Add a watchdog timer to WebGL to prevent bad shaders from running forever

Product:

WebKit

Reporter:

Chris Marrin <cmarrin>

Component:

WebGL

Assignee:

Chris Marrin <cmarrin>

Status:

RESOLVED WONTFIX

Severity:

Normal

CC:

dino, enne, kbr, stearns, tonikitoo, zmo

Priority:

Keywords:

InRadar

Version:

528+ (Nightly build)

Hardware:

OS:

OS X 10.5

Bug Depends on:

64497

Bug Blocks:

71392

Attachments:

Description	Flags
WARNING! Run this in a browser that supports WebGL and your system may hang!	none
Case which renders triangle over and over. Shader takes a long time, but is not infinite loop	none
Even longer shader. This one flickers the background so you can see each render	none
Infinite loop in vertex shader, repeated every 100ms. Locks up WebKit!	none
Infinite loop in fragment shader, repeated every 100ms, locks up WebKit!	none

Chris Marrin

Reported 2010-07-26 10:41:18 PDT

If you create a trivially simply shader which infinite loops, it will hang Mac essentially forever. I need to experiment with the possibility of adding a watchdog timer to check for this condition and destroy the GL context when detected. This will hopefully get out of the hanging condition.

Attachments
WARNING! Run this in a browser that supports WebGL and your system may hang! (3.17 KB, text/html) 2010-09-02 15:19 PDT, Chris Marrin	no flags	Details
Case which renders triangle over and over. Shader takes a long time, but is not infinite loop (3.25 KB, text/html) 2010-09-10 10:56 PDT, Chris Marrin	no flags	Details
Even longer shader. This one flickers the background so you can see each render (3.39 KB, text/html) 2010-09-10 11:24 PDT, Chris Marrin	no flags	Details
Infinite loop in vertex shader, repeated every 100ms. Locks up WebKit! (3.32 KB, text/html) 2010-09-10 16:01 PDT, Chris Marrin	no flags	Details
Infinite loop in fragment shader, repeated every 100ms, locks up WebKit! (3.33 KB, text/html) 2010-09-10 17:41 PDT, Chris Marrin	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Chris Marrin

Comment 1 2010-09-02 15:19:43 PDT

Created attachment 66419 [details] WARNING! Run this in a browser that supports WebGL and your system may hang!

Chris Marrin

Comment 2 2010-09-10 10:56:07 PDT

Created attachment 67203 [details] Case which renders triangle over and over. Shader takes a long time, but is not infinite loop

Chris Marrin

Comment 3 2010-09-10 11:24:56 PDT

Created attachment 67207 [details] Even longer shader. This one flickers the background so you can see each render

Chris Marrin

Comment 4 2010-09-10 16:01:58 PDT

Created attachment 67255 [details] Infinite loop in vertex shader, repeated every 100ms. Locks up WebKit!

Chris Marrin

Comment 5 2010-09-10 17:41:51 PDT

Created attachment 67273 [details] Infinite loop in fragment shader, repeated every 100ms, locks up WebKit!

Kenneth Russell

Comment 6 2011-12-19 15:28:30 PST

I noticed that this bug was just added as a blocker for the CSS Shader umbrella bug. Note that some progress has already been made on this issue on some platforms and ports, though more work is certainly needed. See https://bugs.webkit.org/show_bug.cgi?id=64497 .

Chris Marrin

Comment 7 2011-12-19 16:06:11 PST

(In reply to comment #6) > I noticed that this bug was just added as a blocker for the CSS Shader umbrella bug. Note that some progress has already been made on this issue on some platforms and ports, though more work is certainly needed. See https://bugs.webkit.org/show_bug.cgi?id=64497 . I think this bug is irrelevant given our recent work with robustness and protection against runaway shaders. Our driver team doesn't think it would ever be possible to do this sort of thing in user level code. I suggest we close it as NTBF

Kenneth Russell

Comment 8 2011-12-19 16:18:34 PST

(In reply to comment #7) > > I think this bug is irrelevant given our recent work with robustness and protection against runaway shaders. Our driver team doesn't think it would ever be possible to do this sort of thing in user level code. > > I suggest we close it as NTBF Sounds fine to me. Consider adding one or more of your test cases above to the denial of service samples in the public WebGL repository under sdk/tests/extra/. The infinite loop ones probably are not relevant as I believe ANGLE shouldn't allow those to compile any more.

Dean Jackson

Comment 9 2013-08-12 13:50:57 PDT

Covered by robustness stuff.

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