Attachment 360572 Details for Bug 194016 – Patch

[patch] Patch

bug-194016-20190130153028.patch (text/plain), 2.48 KB, created by Claudio Saavedra on 2019-01-30 05:30:29 PST

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Creator: Claudio Saavedra

Created: 2019-01-30 05:30:29 PST

Size: 2.48 KB

patch

obsolete

>Subversion Revision: 240707
>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index 120c31f46a3df27188261e5363cdaad3648ac205..e19a71d8a34903639aa93b75f94d70ac362f436a 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,24 @@
>+2019-01-30  Claudio Saavedra  <csaavedra@igalia.com>
>+
>+        Race-condition during scrolling thread creation
>+        https://bugs.webkit.org/show_bug.cgi?id=194016
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        There is a threading issue during the initialization
>+        of the scrolling thread caused by createThreadIfNeeded
>+        locking only on the creation of the thread but not on
>+        the initialization of the main loop, making it possible
>+        for a thread to try to spin the main loop before it's
>+        created.
>+
>+        Fix this by unconditionally waiting on the main loop
>+        being created. This makes it necessary to always hold
>+        the lock, even when the thread is already created.
>+
>+        * page/scrolling/ScrollingThread.cpp:
>+        (WebCore::ScrollingThread::createThreadIfNeeded):
>+
> 2019-01-29  Rob Buis  <rbuis@igalia.com>
> 
>         Align with Fetch on data: URLs
>diff --git a/Source/WebCore/page/scrolling/ScrollingThread.cpp b/Source/WebCore/page/scrolling/ScrollingThread.cpp
>index bd3ef00777cdcc1a93325afffeb7800d2df4a5b9..246666d2999cca8eadf53662b32e797e155b709c 100644
>--- a/Source/WebCore/page/scrolling/ScrollingThread.cpp
>+++ b/Source/WebCore/page/scrolling/ScrollingThread.cpp
>@@ -72,24 +72,21 @@ ScrollingThread& ScrollingThread::singleton()
> 
> void ScrollingThread::createThreadIfNeeded()
> {
>-    if (m_thread)
>-        return;
>-
>     // Wait for the thread to initialize the run loop.
>-    {
>-        std::unique_lock<Lock> lock(m_initializeRunLoopMutex);
>+    std::unique_lock<Lock> lock(m_initializeRunLoopMutex);
> 
>+    if (!m_thread) {
>         m_thread = Thread::create("WebCore: Scrolling", [this] {
>             WTF::Thread::setCurrentThreadIsUserInteractive();
>             initializeRunLoop();
>         });
>-        
>+    }
>+
> #if PLATFORM(COCOA)
>-        m_initializeRunLoopConditionVariable.wait(lock, [this]{ return m_threadRunLoop; });
>+    m_initializeRunLoopConditionVariable.wait(lock, [this]{ return m_threadRunLoop; });
> #else
>-        m_initializeRunLoopConditionVariable.wait(lock, [this]{ return m_runLoop; });
>+    m_initializeRunLoopConditionVariable.wait(lock, [this]{ return m_runLoop; });
> #endif
>-    }
> }
> 
> void ScrollingThread::dispatchFunctionsFromScrollingThread()

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