616508 - JM: Crash [@ js::mjit::ic::Name] or "Assertion failure: shape,"

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

try {
    (function () {
        __proto__ = Uint32Array()
    }())
} catch (e) {}(function () {
    length, ([eval()] ? x : 7)
})()

asserts js debug shell on TM changeset 25fd3451c0ae with -m at Assertion failure: shape, and crashes js opt shell with -m at js::mjit::ic::Name.

Program received signal SIGSEGV, Segmentation fault.
0x0824ab76 in js::mjit::ic::Name(js::VMFrame&, js::mjit::ic::PICInfo*) ()
(gdb) bt
#0  0x0824ab76 in js::mjit::ic::Name(js::VMFrame&, js::mjit::ic::PICInfo*) ()
#1  0xffffd044 in ?? ()
#2  0xf7500820 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) x/i $eip
=> 0x824ab76 <_ZN2js4mjit2ic4NameERNS_7VMFrameEPNS1_7PICInfoE+454>:	movzbl 0x1c(%edx),%edi
(gdb) x/b $edx
0x0:	Cannot access memory at address 0x0

Comment 1

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

Although this seems to be a null crash, it's probably best to set s-s just-in-case.

Comment 2

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

autoBisect shows this is probably related to the following changeset:

The first bad revision is:
changeset:   57018:728eedc664b2
user:        David Mandelin
date:        Thu Nov 04 18:05:39 2010 -0700
summary:     Bug 608868: check for non-native objects when binding in scope name ICs, r=dvander, a=beta8+

Comment 3

[David Anderson [:dvander] - inactive, e-mail if emergency]

Attachment: fix

We decide not to cache property lookups when anything from [obj, holder] on the proto chain is non-native. That is, we don't store "shape" casted from "prop".

But ic::Name checks whether we've cached by looking at just |obj| and |holder|. Instead, it should just check whether the caching occurred or not.

Comment 4

[David Anderson [:dvander] - inactive, e-mail if emergency]

http://hg.mozilla.org/tracemonkey/rev/cf2a11def626

Comment 5

[Robert Sayre]

http://hg.mozilla.org/mozilla-central/rev/cf2a11def626

Comment 6

[Christian Holler (:decoder)]

A testcase for this bug was automatically identified at js/src/jit-test/tests/jaeger/bug616508.js.