Bug 64465

Summary:

Possible race condition in ThreadIdentifierData::initializeKeyOnce and shouldCallRealDebugger.

Product:

WebKit

Reporter:

David Levin <levin>

Component:

Web Template Framework

Assignee:

David Levin <levin>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

andersca, dimich, webkit.review.bot

Priority:

Version:

528+ (Nightly build)

Hardware:

Mac

OS:

All

Attachments:

Description	Flags
Patch	none

David Levin

Reported 2011-07-13 10:41:57 PDT

The race condition is highly unlikely and was only noticed through code inspection but it is trivial to make the code correct. The race would happen if the static initialization starts to happen on two threads. Thread 1 does the initialization and Thread 2 is at the initialization code but hasn't yet executed it. Thread 1 finishes the pthread_once call and then Thread 2 initializes onceControl to PTHREAD_ONCE_INIT. Thread 2 does the pthread_once call which happens again now.

Attachments
Patch (3.97 KB, patch) 2011-07-13 11:03 PDT, David Levin	no flags	Details Formatted Diff Diff
View All Add attachment proposed patch, testcase, etc.

David Levin

Comment 1 2011-07-13 10:52:20 PDT

All other instances do this correctly now. Source/JavaScriptCore/runtime/JSLock.cpp:pthread_once_t createJSLockCountOnce = PTHREAD_ONCE_INIT; Source/JavaScriptCore/wtf/FastMalloc.cpp:static pthread_once_t isForbiddenKeyOnce = PTHREAD_ONCE_INIT; Source/JavaScriptCore/wtf/MainThread.cpp:static pthread_once_t initializeMainThreadKeyOnce = PTHREAD_ONCE_INIT; Source/JavaScriptCore/wtf/ThreadIdentifierDataPthreads.cpp:static pthread_once_t onceControl = PTHREAD_ONCE_INIT; Source/JavaScriptGlue/JSUtils.cpp:static pthread_once_t globalObjectKeyOnce = PTHREAD_ONCE_INIT; Source/WebCore/bridge/jni/jni_jsobject.mm:static pthread_once_t javaScriptAccessLockOnce = PTHREAD_ONCE_INIT; Source/WebKit/mac/Misc/WebKitErrors.m:static pthread_once_t registerErrorsControl = PTHREAD_ONCE_INIT; Source/WebKit/mac/Misc/WebKitSystemBits.m:static pthread_once_t initControl = PTHREAD_ONCE_INIT; Source/WebKit/mac/Misc/WebNSURLExtras.mm:static pthread_once_t IDNScriptWhiteListFileRead = PTHREAD_ONCE_INIT; Source/WebKit2/WebProcess/WebCoreSupport/mac/WebErrorsMac.mm:static pthread_once_t registerErrorsControl = PTHREAD_ONCE_INIT;

David Levin

Comment 2 2011-07-13 11:03:31 PDT

Created attachment 100687 [details] Patch

Dmitry Titov

Comment 3 2011-07-13 11:43:12 PDT

Comment on attachment 100687 [details] Patch Nice.

WebKit Review Bot

Comment 4 2011-07-13 12:19:38 PDT

Comment on attachment 100687 [details] Patch Clearing flags on attachment: 100687 Committed r90939: <http://trac.webkit.org/changeset/90939>

WebKit Review Bot

Comment 5 2011-07-13 12:19:42 PDT

All reviewed patches have been landed. Closing bug.

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