894597 - TaskThrottler::TaskComplete shouldn't call nsTArray::RemoveElementAt(0) on an empty array

Status: RESOLVED DUPLICATE of bug 895722

(Core :: Graphics: Layers, defect)

Description

[Justin Lebar (not reading bugmail)]

My B2G trunk build is crashing sometimes when I load a bunch of apps and then kill them with

 $ adb shell kill -9 $(adb shell b2g-info -c)

I think this is because TaskThrottler::TaskComplete calls nsTArray::RemoveElementAt(0) on an empty nsTArray.

I'll attach a patch which naively puts a guard in place, but I have no idea if this is right.

Comment 1

[Justin Lebar (not reading bugmail)]

This blocks bug 893012 because it's keeping me from being able to test it.  I'd guess that this bug probably is not present on b2g18, since we just refactored layers.

Comment 2

[Justin Lebar (not reading bugmail)]

Attachment: Patch, v1

Comment 3

[Anthony Jones (:ajones, :kentuckyfriedtakahe, :k17e)]

Comment on attachment 776666 [details] [diff] [review]
Patch, v1

Review of attachment 776666 [details] [diff] [review]:
-----------------------------------------------------------------

Happy to see this landed. It will be superseded by bug 888084 otherwise.

Comment 4

[Justin Lebar (not reading bugmail)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/1d69e824c557

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/1d69e824c557

Comment 6

[Andrew McCreight [:mccr8] (PTO until 12-2)]

Justin, it looks like you landed an empty changeset.

Comment 7

[Justin Lebar (not reading bugmail)]

Well, that's cool.

Comment 8

[Justin Lebar (not reading bugmail)]

The code now does

  if (mMaxDurations > 0) {
      if (mDurations.Length() >= mMaxDurations) {
          mDurations.RemoveElementAt(0);
      }
      mDurations.AppendElement(aTimeStamp - mStartTime);
  }

so we're good.