762406 - 100% CPU core hang in mozjs.dll ensureSpaceSlow call

Status: RESOLVED INCOMPLETE

(Core :: JavaScript Engine, defect)

Description

[Cees T.]

User Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; MS-RTC LM 8; .NET4.0C; .NET4.0E)

Steps to reproduce:

I opened about 600 tabs on this 64-bit Windows 7 system. Suddently it stated to keep getting slower, no matter what i closed. Now it's grinded to a halt with the same stack in Process Explorer cycling at 100% of one 2.93 GHz Xeon CPU and using 2,857,412 K private bytes of 6 GB RAM. 2,330,792 K working set, and 3,906,964 K virtual size. I managed to open about:memory yesterday, but it just showed a grey background and an empty white box with rounded corners.


Actual results:

It got progressively slower and has been doing nothing but looking this stack in firefox.exe for the past half hour or so:

mozjs.dll!?ensureSpaceSlow@StackSpace@js@@ABE_NPAUJSContext@@W4MaybeReportError@2@PAVValue@JS@@HPAUJSCompartment@@@Z+0x245
xul.dll!XRE_TermEmbedding+0x5c82
xul.dll!NS_CStringContainerFinish_P+0x106c
mozjs.dll!?ensureSpaceSlow@StackSpace@js@@ABE_NPAUJSContext@@W4MaybeReportError@2@PAVValue@JS@@HPAUJSCompartment@@@Z+0x245
xul.dll!JSD_GetScriptFunctionId+0x6a0a4
xul.dll!JSD_GetScriptFunctionId+0x6a19b
mozjs.dll!?js_CloneRegExpObject@@YIPAUJSObject@@PAUJSContext@@PAU1@1@Z+0x5537b

As this textbox is small, i'll paste a new copy to compare:

mozjs.dll!?ensureSpaceSlow@StackSpace@js@@ABE_NPAUJSContext@@W4MaybeReportError@2@PAVValue@JS@@HPAUJSCompartment@@@Z+0x240
xul.dll!XRE_TermEmbedding+0x5c82
xul.dll!NS_CStringContainerFinish_P+0x106c
mozjs.dll!?ensureSpaceSlow@StackSpace@js@@ABE_NPAUJSContext@@W4MaybeReportError@2@PAVValue@JS@@HPAUJSCompartment@@@Z+0x240
xul.dll!JSD_GetScriptFunctionId+0x6a0a4
xul.dll!JSD_GetScriptFunctionId+0x6a19b
mozjs.dll!?js_CloneRegExpObject@@YIPAUJSObject@@PAUJSContext@@PAU1@1@Z+0x5537b



Expected results:

Stay responsive, if not snappy. White rectangles should never stay on a GUI.

Comment 1

[Cees T.]

s/stated/started, looking/looping, and it/Firefox 12.

Windows has been swapping long ago, but now it's only Firefox hogging the CPU. Good thing this is a multicore machine.

Comment 2

[Cees T.]

Attachment: Process Explorer info

7.61 GB free on C:

Comment 3

[Cees T.]

Just now, i was composing a textarea message and siwtching windows, when suddently Firefox froze, using all of one core again:

mozjs.dll!?CollectRuntimeStats@JS@@YA_NPAUJSRuntime@@PAURuntimeStats@1@@Z+0x19b4c
mozjs.dll!?CollectRuntimeStats@JS@@YA_NPAUJSRuntime@@PAURuntimeStats@1@@Z+0x513aa
xul.dll!NS_CycleCollectorSuspect2_P+0x30b18

I'll let it collect over night but it'll probably crash tomorrow. On the bright side, it's not using kernel cycles now.

Comment 4

[Cees T.]

Still frozen and now its window contents are completely white. I'll have to euthanize it. Fx v13.0.1.4548 according to Process Explorer.

Comment 5

[Cees T.]

I don't think those stacks are accurate as dbghelp silently failed to update the symbols: https://bugzilla.mozilla.org/show_bug.cgi?id=905131#c25

Current near-hang due to regex loop in one of my 300+ tabs:

mozglue.dll!arena_malloc_small+0xcf
mozglue.dll!arena_malloc+0x2b
mozglue.dll!je_malloc+0x22
mozjs.dll!JSRope::flattenInternal<1>+0xe1
mozjs.dll!JSRope::flatten+0x19
mozjs.dll!js_TrimString+0xfb
mozjs.dll!str_trim+0x12

xul.dll!nsCOMPtr_base::assign_from_qi+0x17
xul.dll!nsCOMPtr_base::assign_from_qi+0x2b
xul.dll!nsCOMPtr_base::assign_from_qi+0x17
xul.dll!nsDOMWindowList::EnsureFresh+0x1d
xul.dll!nsGlobalWindow::Length+0x28
xul.dll!mozilla::dom::WindowNamedPropertiesHandler::getOwnPropertyDescriptor+0x1b8

mozjs.dll!JSContext::currentScript+0x61
mozjs.dll!JSObject::getGeneric+0x7de
mozjs.dll!JSContext::currentScript+0x61
mozjs.dll!JSObject::getGeneric+0x7de
mozjs.dll!js::DirectProxyHandler::get+0x55
xul.dll!nsOuterWindowProxy::get+0x5a
mozjs.dll!js::proxy_GetGeneric+0x96
mozjs.dll!js::GetProperty+0x11ac20
mozjs.dll!js::jit::DoTypeOfFallback+0x1e5

Comment 6

[Wayne Mery (:wsmwk)]

Still see this?

Comment 7

[Cees T.]

Attachment: Nightly 40.0.0.5598 hang.txt

I'm using Chrome on this machine, but i saw i had an open Notepad++ tab with some Nightly stacks.

Comment 8

[Cees T.]

Attachment: Firefox 38 overheating.txt

And some current stacks from the stable Firefox at home, which i can't shut down because the menus containing those buttons don't appear.

Even the .txt icons in the Windows 7 file picker appear as black squares.

Comment 9

[Andrei Purice]

Marking this as Resolved > Incomplete since the reporter cannot be contacted further to provide an answer if the issue is still occurring.
Please feel free to re-open or file a new bug if anyone is still encountering this issue.