1398393 - Rust panic when using Stylo with Quantum DOM threads

Status: RESOLVED FIXED

(Core :: DOM: Content Processes, defect)

Description

[Blake Kaplan (:mrbkap) (inactive)]

With dom.ipc.scheduler and layout.css.servo.enabled set to true, we get a rust panic pretty early on in startup:

thread '<unnamed>' panicked at 'assertion failed: thread_state::get() == thread_state::LAYOUT', /home/mrbkap/work/main/mozilla/servo/components/style/context.rs:789:8

The problem appears to be that on the true main thread we call Servo_Initialize [1] in order to do some debug verification, set up the global logger, set some global state, and importantly for this bug, set the "thread state" in the thread local data.

It seems like the easiest fix would be to add a way for cooperative threads to set the Rust thread state, but I'm pretty new to this code so I'm open to alternative fixes.

[1] http://searchfox.org/mozilla-central/rev/d29c832536839b60a9ee5b512eeb934274b879b0/servo/ports/geckolib/glue.rs#157

Comment 1

[Blake Kaplan (:mrbkap) (inactive)]

Attachment: Bug 1398393 - Set Servo thread state on cooperative threads.

Review commit: https://reviewboard.mozilla.org/r/177922/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/177922/

Comment 2

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

Comment on attachment 8906176 [details]
Bug 1398393 - Set Servo thread state on cooperative threads.

https://reviewboard.mozilla.org/r/177922/#review186730

::: xpcom/threads/CooperativeThreadPool.cpp:160
(Diff revision 1)
>  
>    nsCString name = mPool->mThreadNaming.GetNextThreadName("Main");
>    PR_SetCurrentThreadName(name.get());
>  
>    mozilla::IOInterposer::RegisterCurrentThread();
> +  Servo_InitializeCooperativeThread();

Can we put this somewhere in here?
http://searchfox.org/mozilla-central/rev/1c13d5cf85f904afb8976c02a80daa252b893fca/xpcom/threads/Scheduler.cpp#630-656

Comment 3

[Blake Kaplan (:mrbkap) (inactive)]

Comment on attachment 8906176 [details]
Bug 1398393 - Set Servo thread state on cooperative threads.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/177922/diff/1-2/

Comment 4

[Blake Kaplan (:mrbkap) (inactive)]

Comment on attachment 8906176 [details]
Bug 1398393 - Set Servo thread state on cooperative threads.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/177922/diff/2-3/

Comment 5

[Blake Kaplan (:mrbkap) (inactive)]

I created https://github.com/servo/servo/pull/18569 for the servo/ bit.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/785910c8bee7
Set Servo thread state on cooperative threads. r=billm

Comment 7

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/785910c8bee7