653631 - Crash [@ JSStackFrame::isDummyFrame] with mozRequestAnimationFrame

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jesse Ruderman]

Attachment: testcase (crashes Firefox when loaded)

Related to bug 652401?

Comment 1

[Jesse Ruderman]

Attachment: stack trace

Comment 2

[Boris Zbarsky [:bzbarsky]]

> Related to bug 652401?

Sorta.

So we crash because cx->hasfp() is true, cx->fp()->isDummyFrame() is true, and cx->fp->prev() is null.  So js::CurrentScriptFileAndLineSlow called from js::CurrentScriptFileAndLine called from Function() ends up crashing with a null-deref.

We push dummy frames on AutoCompartment::enter.  In this case that happens with this stack:

#0  js::AutoCompartment::enter (this=0x1da0cfe0) at /Users/bzbarsky/mozilla/vanilla/mozilla/js/src/jswrapper.cpp:379
#1  0x04649d19 in JS_EnterCrossCompartmentCall (cx=0x5131620, target=0x217f0410) at /Users/bzbarsky/mozilla/vanilla/mozilla/js/src/jsapi.cpp:1210
#2  0x04649dc3 in JSAutoEnterCompartment::enter (this=0xbfffc324, cx=0x5131620, target=0x217f0410) at /Users/bzbarsky/mozilla/vanilla/mozilla/js/src/jsapi.cpp:1260
#3  0x00fa2d2c in GetContextFromObject (obj=0x217f0410) at /Users/bzbarsky/mozilla/vanilla/mozilla/js/src/xpconnect/src/xpcwrappedjsclass.cpp:569
#4  0x00fa39c7 in nsXPCWrappedJSClass::CallMethod (this=0x1da3a090, wrapper=0x1da2b8e0, methodIndex=3, info=0x58b97c8, nativeParams=0xbfffc7e0) at /Users/bzbarsky/mozilla/vanilla/mozil a/js/src/xpconnect/src/xpcwrappedjsclass.cpp:1294
#5  0x00f9ba59 in nsXPCWrappedJS::CallMethod (this=0x1da2b8e0, methodIndex=3, info=0x58b97c8, params=0xbfffc7e0) at /Users/bzbarsky/mozilla/vanilla/mozilla/js/src/xpconnect/src/xpcwrap edjs.cpp:586

GetContextFromObject only starts entering compartments and the like if the JS context stack is empty.  So that's where bug 652401 comes in.

However this seems like a general bug in Function.  It seems to assume that if hasfp() then there is a non-dummy frame on the stack... but that's just not true.  Luke added this code a few days ago in bug 602994.

Comment 3

[Luke Wagner [:luke]]

Attachment: fix

Argh, this is a failed specialization of js_GetScriptedCaller (missing "fp &&" conjunct).  I think I initially did this since sometimes eval is on the hot path and js_GetScriptedCaller is a call + LeaveTrace on every eval.  I don't think it really matters, though, so I'll just put js_GetScriptedCaller back.

Comment 4

[Luke Wagner [:luke]]

http://hg.mozilla.org/tracemonkey/rev/e4861593d134

Comment 5

[Chris Leary [:cdleary] (not checking bugmail)]

cdleary-bot mozilla-central merge info:
http://hg.mozilla.org/mozilla-central/rev/e4861593d134

Comment 6

[Johnathan Nightingale [:johnath]]

Done, made the merge, not likely to back out, don't need to track for ff6