1411818 - New tabs refuse to load, appear blank white, due to bad content process at 100% CPU (83% in js::gc::GCRuntime::gcCycle)

Status: RESOLVED INCOMPLETE

(Core :: JavaScript: GC, defect)

Description

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

Attachment: trace.txt

I keep running into this symptom occasionally, recall seeing it when Nightly was 57 too. Saw it again just now in Nightly (58):

Suddenly, tabs I open stop responding to having urls entered. The content area just clears and goes blank white when I hit enter. The chrome still works, just nothing shows up on the page, or even looks like it's trying. I can type in any url I want, but content appears dead.

Only some tabs are affected, and they're all are of the same content process. Looking at Activity Monitor shows that content process at ~107% (it's OSX).

So this time I did a 30 second profile of that process to see where that time is spent.

Attached is a cut'n'paste text file of the output (full profile available on request). To summarize:

  83.1%	is spent in mozilla::dom::TabChild::RecvRealMouseButtonEvent, which in turn ends up in

    56.7%  js::gc::GCRuntime::gcCycle

The remaining

  26.4%	is spent in mozilla::EventStateManager::DispatchMouseOrPointerEvent, also in

    26.4% js::gc::GCRuntime::gcCycle

So basically, GC/CC run amok enough to make this content process unresponsive to anything else.

I can't reliably repro, so hopefully these are clues.

I didn't get to try closing any tabs to see if it would help, as the content process crashed shortly after the trace. See bp-dc63b173-6903-4747-a8a4-0ddfe0171026

Comment 1

[Johann Hofmann [:johannh]]

I have also seen this occasionally happen on my OSX machine. It's impossible to reliably reproduce for me.

Comment 2

[Firefox Bug Husbandry Bot]

https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Update_affecteds

Comment 3

[Chris Peterson [:cpeterson]]

So basically, GC/CC run amok enough to make this content process unresponsive to anything else.

moving to GC component

Comment 4

[Andrew McCreight [:mccr8]]

I don't think there's enough to go on here.