946883 - Some timeout related jit-tests fail on OS X with NSPR emulation

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jan de Mooij [:jandem]]

I looked into the shell-watchdog.js failure. We're failing this assert in JitRuntime::handleAccessViolation:

    JS_ASSERT(!rt->currentThreadOwnsOperationCallbackLock());

The callstack looks like this:

  js::jit::JitRuntime::handleAccessViolation
  HandleMachException
  AsmJSMachExceptionHandlerThread

currentThreadOwnsOperationCallbackLock ends up calling PR_GetCurrentThread(). I think this fails because AsmJSMachExceptionHandlerThread is not an NSPR thread (we use pthread_create directly) and PR_GetCurrentThread() returns null.

NSPR itself calls pt_AttachThread() in this case I think so it always return something non-null.

billm, luke: any thoughts on how to fix this? We could turn it into an NSPR thread maybe? Not sure how hard that is.

Comment 1

[Luke Wagner [:luke]]

Does changing the pthread_create in AsmJSMachExcpetionHandler::install to PR_CreateThread fix the assertion?

Comment 2

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

If need be, we PosixNSPR could do what NSPR does and create an nspr::Thread in PR_GetCurrentThread() if the TLS is unset. It would be a pain to ensure that gets deleted, but it's not too big a deal.

Luke's suggestion would be easier if it works, though.

Comment 3

[Jan de Mooij [:jandem]]

Attachment: Use NSPR thread for AsmJSMachExceptionHandler

jit-tests are green with this patch, both with NSPR and PosixNSPR.

When I filed this bug, I thought thread_set_exception_ports wanted a pthread_t of the new thread, but I misread and it doesn't so this was pretty straight-forward.

Comment 4

[Luke Wagner [:luke]]

Comment on attachment 8343655 [details] [diff] [review]
Use NSPR thread for AsmJSMachExceptionHandler

Thanks!

Comment 5

[Jan de Mooij [:jandem]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/d86f10836597

Comment 6

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/d86f10836597