1705007 - Crash in [@ nsObserverService::AddObserver]

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Gabriele Svelto [:gsvelto]]

Crash report: https://crash-stats.mozilla.org/report/index/fde3642d-0938-49d6-b60e-5fafe0210414

MOZ_CRASH Reason: MOZ_CRASH(Using observer service off the main thread!)

Top 10 frames of crashing thread:

0 xul.dll nsObserverService::AddObserver xpcom/ds/nsObserverService.cpp:209
1 xul.dll static `anonymous namespace'::ProcessPriorityManagerChild::StaticInit dom/ipc/ProcessPriorityManager.cpp:779
2 xul.dll static mozilla::ProcessPriorityManager::CurrentProcessIsForeground dom/ipc/ProcessPriorityManager.cpp:857
3 xul.dll mozilla::WebGLContext::OnMemoryPressure dom/canvas/WebGLContext.cpp:237
4 xul.dll mozilla::dom::WebGLParent::RecvOnMemoryPressure dom/canvas/WebGLParent.cpp:287
5 xul.dll mozilla::dom::PWebGLParent::OnMessageReceived ipc/ipdl/PWebGLParent.cpp:1758
6 xul.dll mozilla::ipc::PBackgroundParent::OnMessageReceived ipc/ipdl/PBackgroundParent.cpp:6293
7 xul.dll mozilla::ipc::MessageChannel::DispatchMessage ipc/glue/MessageChannel.cpp:2074
8 xul.dll nsThread::ProcessNextEvent xpcom/threads/nsThread.cpp:1153
9 xul.dll mozilla::ipc::MessagePumpForNonMainThreads::Run ipc/glue/MessagePump.cpp:332

The GPU process is receiving a memory pressure event from the parent process via IPC. Before reacting on the event it's calling ProcessPriorityManager::CurrentProcessIsForeground(). The first thing that happens is that the ProcessPriorityManagerChild singleton is initialized and this requires the observer service. However the observer service cannot be called off the main thread so it trips an assertion.

I need to investigate how the process priority manager is supposed to work in this particular scenario because AFAIK that particular singleton should have already been initialized during startup.

Comment 1

[Brad Werth [:bradwerth]]

In triage, we concluded that GPUParent::Init needs to call ProcessPriorityManager::Init(). I'll build a patch.

Comment 2

[Brad Werth [:bradwerth]]

Attachment: Bug 1705007: Ensure GPU process has created the observer service.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e7d4eb02cabd
Ensure GPU process has created the observer service. r=gfx-reviewers,aosmond

Comment 4

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/e7d4eb02cabd