Bug 48795 – [Chromium] REGRESSION(r70552): DumpRenderTree never exits.

• Component: WebKit API
• Status: RESOLVED WONTFIX

[Dimitri Glazkov (Google)]

It seems there was some regression somewhere that made DumpRenderTree process never exit. It just hangs there. In non-Windows, server_process.py actually kills DRT after a timeout, but on Windows we become screwed.

As of right now, the Chromium Win Release (Tests) builder has to be manually aided (taskkill) after each cycle. I have no idea when it began. Looking at the waterfall, potential offender is http://trac.webkit.org/changeset/70552/.

I am trying to revert locally and see what happens.

[Kent Tamura]

I couldn't reproduce this issue on my Windows 7 machine.

[Dimitri Glazkov (Google)]

(In reply to comment #1)
> I couldn't reproduce this issue on my Windows 7 machine.

Odd. I can reproduce it consistently. The tests finish, but three or so DumpRenderTree.exe processes remain.

[Dimitri Glazkov (Google)]

I've confirmed that rolling out http://trac.webkit.org/changeset/70552/ fixes the issue. The trouble is, I am pretty sure it's the DEPS roll that caused it, not the actual change.

[Dimitri Glazkov (Google)]

I narrowed it down to http://src.chromium.org/viewvc/chrome?view=rev&revision=63548.

[Dimitri Glazkov (Google)]

(In reply to comment #4)
> I narrowed it down to http://src.chromium.org/viewvc/chrome?view=rev&revision=63548.

I suspect this problem also exists in test_shell, but because we kill test_shell by force when it's no longer necessary, the problem is not clearly visible.

[Dimitri Glazkov (Google)]

How's it going? Any updates?

[Victoria Kirst]

Hmm, I can't reproduce the issue on my Windows 7 machine, either. I am running "python new-run-webkit-tests --chromium --use-drt --platform chromium-win-vista media" and the test can complete fine and I don't have any stranded DumpRenderTree.exe instances afterward. Am I doing something wrong? Also, do you have an idea of what tests are causing DRT to hang?

[Dimitri Glazkov (Google)]

(In reply to comment #7)
> Hmm, I can't reproduce the issue on my Windows 7 machine, either. I am running "python new-run-webkit-tests --chromium --use-drt --platform chromium-win-vista media" and the test can complete fine and I don't have any stranded DumpRenderTree.exe instances afterward. Am I doing something wrong? Also, do you have an idea of what tests are causing DRT to hang?

I ran the entire test set: new-run-webkit-tests --chromium --use-drt

[Victoria Kirst]

> I ran the entire test set: new-run-webkit-tests --chromium --use-drt

OK, that did it! Thanks!

Here's what I've seen so far: It looks like the tests that fail are video-play-stall.html, video-play-stall-seek.html, and video-seekable-stall.html. But the bug is not 100% consistently reproduced (probably more like 75%?) and DumpRenderTree.exe occasionally exits cleanly, which explains why there are 2-3 processes orphaned at the end of running the entire test suite instead of an exact number.

I'll try to run it with the Debug build tomorrow to get a stack trace and pinpoint exactly what's causing the problem.

[Dirk Pranke]

(In reply to comment #7)
> Hmm, I can't reproduce the issue on my Windows 7 machine, either. I am running "python new-run-webkit-tests --chromium --use-drt --platform chromium-win-vista media" and the test can complete fine and I don't have any stranded DumpRenderTree.exe instances afterward. Am I doing something wrong? Also, do you have an idea of what tests are causing DRT to hang?

This is a side note, but if you're on win 7, you should be using --platform chromium-win , not --platform chromium-win-vista . The win 7 baselines are in the regular "win" directory. Also, you don't need to specify both --chromium and --platform ; specifying just --chromium will cause the appropriate chromium windows version to be selected.

Not that that should cause anything to hang, of course.

[Hin-Chung Lam]

I traced down the code and fond the cause of the hang . vrk's change was supposed to fix a hang case, however it uncovered another hanging case (in fact two potentially) which causes DRT to hang. I'll bring up the discussion and will work on a fix tomorrow.

[Hin-Chung Lam]

Landed a patch to skip those offending layout tests: http://trac.webkit.org/changeset/71349.

Still working on the proper fix. Unfortunately this involves a bigger problem in the media code.. :( I'm working on an ad hoc fix to the code, but we'll need to fix this again properly.. :( :(

[Dimitri Glazkov (Google)]

(In reply to comment #12)
> Landed a patch to skip those offending layout tests: http://trac.webkit.org/changeset/71349.
> 
> Still working on the proper fix. Unfortunately this involves a bigger problem in the media code.. :( I'm working on an ad hoc fix to the code, but we'll need to fix this again properly.. :( :(

Thanks, Alpha!

[Andrew Scherkus]

No ad-hoc fixes please!

We have the time and bandwidth to do the proper fix.  I'm fine leaving us with skipped tests for the time being (we can also discuss offline!)

[Hin-Chung Lam]

OK, I'll wait until we have a discussion about what the fix should look like. It's likely someone else will be doing the proper fix.

[Dimitri Glazkov (Google)]

Is this fixed now?

[Stephen Chenney]

LayoutTest failures for Chromium are being marked WontFix. The Bug is still accessible and referenced from TestExpectations.