1494528 - GPU process start failure is not handled correctly when WebRender is enabled

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Sotaro Ikeda [:sotaro]]

With the following crash log, when gpu loanch is failed, it seemed to try to allocate WebRender in chrome process. But it is disabled and an unexpected STR.

https://crash-stats.mozilla.com/report/index/cc18ed3b-af9b-48c5-8d10-24ba30180924

Comment 1

[Sotaro Ikeda [:sotaro]]

Attachment: patch - Rebuild accelerated features during disabling GPU process

Comment 2

[Sotaro Ikeda [:sotaro]]

When connection to GPU process is failed, GPUProcessManager::DisableGPUProcess() is called and it disables GPU process usage. And gfxPlatform::NotifyGPUProcessDisabled() is called in the DisableGPUProcess(). The NotifyGPUProcessDisabled() disables WebRender if it is enabled.

https://dxr.mozilla.org/mozilla-central/source/gfx/thebes/gfxPlatform.cpp#3185

Comment 3

[Sotaro Ikeda [:sotaro]]

(In reply to Sotaro Ikeda [:sotaro] from comment #0)
> With the following crash log, when gpu loanch is failed, it seemed to try to
> allocate WebRender in chrome process. But it is disabled and an unexpected
> STR.
> 
> https://crash-stats.mozilla.com/report/index/cc18ed3b-af9b-48c5-8d10-24ba30180924

The crash suggests that GPU process is disabled, but it try to allocate WebRenderAPI in parent process. But in parent process, RenderThread is not initialized. Then it causes crash.

One possibility of causing the crash is that GPUProcessManager::EnsureGPUReady() is not called yet when nsBaseWidget::CreateCompositorSession() is called, and the EnsureGPUReady() is called in GPUProcessManager::CreateTopLevelCompositor(). And it failed to connect to GPU process and disabled GPU process and disabled gfxVars::UseWebRender(), but the CreateCompositorSession() already decided to use WebRender before calling the CreateTopLevelCompositor().

Comment 4

[Sotaro Ikeda [:sotaro]]

Attachment: patch - Call GPUProcessManager::EnsureGPUReady() before accessing gfxVars::UseWebRender()

Comment 5

[Sotaro Ikeda [:sotaro]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=2d065f9491b930025f262cef118e5d2bc60715cf

Comment 6

[Andrew Osmond [:aosmond] (he/him)]

Comment on attachment 9012539 [details] [diff] [review]
patch - Call GPUProcessManager::EnsureGPUReady() before accessing gfxVars::UseWebRender()

Review of attachment 9012539 [details] [diff] [review]:
-----------------------------------------------------------------

Nice catch.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/a94730ef300e
Call GPUProcessManager::EnsureGPUReady() before accessing gfxVars::UseWebRender() r=aosmond

Comment 8

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/a94730ef300e