[GTK] [WK2] Reproducible crash in performDragControllerAction

[Sudarsana Nagineni (babu)]

Steps to reproduce:
1. Open ./MiniBrowser http://www.google.com
2. Drag and drop the image on the page.

#0  0x00007f5ebea95d71 in WTF::RefCountedBase::~RefCountedBase (this=0x2eaafb0, __in_chrg=<optimized out>) at ../../Source/WTF/wtf/RefCounted.h:122
122	        ASSERT(m_deletionHasBegun);
(gdb) bt
#0  0x00007f5ebea95d71 in WTF::RefCountedBase::~RefCountedBase (this=0x2eaafb0, __in_chrg=<optimized out>) at ../../Source/WTF/wtf/RefCounted.h:122
#1  0x00007f5ebeac7834 in WTF::RefCounted<WebCore::DataObjectGtk>::~RefCounted (this=0x2eaafb0, __in_chrg=<optimized out>) at ../../Source/WTF/wtf/RefCounted.h:197
#2  0x00007f5ebeac8464 in WebCore::DataObjectGtk::~DataObjectGtk (this=0x2eaafb0, __in_chrg=<optimized out>) at ../../Source/WebCore/platform/gtk/DataObjectGtk.h:32
#3  0x00007f5ebecb0c8a in WebKit::WebPage::performDragControllerAction (this=0x23e9da0, action=0, dragData=...) at ../../Source/WebKit2/WebProcess/WebPage/WebPage.cpp:2183
#4  0x00007f5ebeceedaf in CoreIPC::callMemberFunction<WebKit::WebPage, void (WebKit::WebPage::*)(unsigned long, WebCore::DragData), unsigned long, WebCore::DragData> (args=..., object=0x23e9da0, function=
    (void (WebKit::WebPage::*)(WebKit::WebPage * const, unsigned long, WebCore::DragData)) 0x7f5ebecb0a26 <WebKit::WebPage::performDragControllerAction(unsigned long, WebCore::DragData)>)
    at ../../Source/WebKit2/Platform/CoreIPC/HandleMessage.h:25
#5  0x00007f5ebeced447 in CoreIPC::handleMessage<Messages::WebPage::PerformDragControllerAction, WebKit::WebPage, void (WebKit::WebPage::*)(unsigned long, WebCore::DragData)> (argumentDecoder=
    0x7f5ea4001e90, object=0x23e9da0, function=
    (void (WebKit::WebPage::*)(WebKit::WebPage * const, unsigned long, WebCore::DragData)) 0x7f5ebecb0a26 <WebKit::WebPage::performDragControllerAction(unsigned long, WebCore::DragData)>)
    at ../../Source/WebKit2/Platform/CoreIPC/HandleMessage.h:302
#6  0x00007f5ebeceb210 in WebKit::WebPage::didReceiveWebPageMessage (this=0x23e9da0, messageID=..., arguments=0x7f5ea4001e90) at DerivedSources/WebKit2/WebPageMessageReceiver.cpp:324
#7  0x00007f5ebecb1b88 in WebKit::WebPage::didReceiveMessage (this=0x23e9da0, connection=0x20fc550, messageID=..., arguments=0x7f5ea4001e90) at ../../Source/WebKit2/WebProcess/WebPage/WebPage.cpp:2581
#8  0x00007f5ebecc1a92 in WebKit::WebProcess::didReceiveMessage (this=0x20fc030, connection=0x20fc550, messageID=..., arguments=0x7f5ea4001e90) at ../../Source/WebKit2/WebProcess/WebProcess.cpp:683
#9  0x00007f5ebecbfb56 in WebKit::WebConnectionToUIProcess::didReceiveMessage (this=0x20fc500, connection=0x20fc550, messageID=..., arguments=0x7f5ea4001e90)
    at ../../Source/WebKit2/WebProcess/WebConnectionToUIProcess.cpp:87
#10 0x00007f5ebea9bdcb in CoreIPC::Connection::dispatchMessage (this=0x20fc550, message=...) at ../../Source/WebKit2/Platform/CoreIPC/Connection.cpp:691
#11 0x00007f5ebea9bf69 in CoreIPC::Connection::dispatchOneMessage (this=0x20fc550) at ../../Source/WebKit2/Platform/CoreIPC/Connection.cpp:717
#12 0x00007f5ebeaa6106 in WTF::FunctionWrapper<void (CoreIPC::Connection::*)()>::operator() (this=0x7f5ea40011d0, c=0x20fc550) at ../../Source/WTF/wtf/Functional.h:173
#13 0x00007f5ebeaa5f0c in WTF::BoundFunctionImpl<WTF::FunctionWrapper<void (CoreIPC::Connection::*)()>, void (CoreIPC::Connection*)>::operator()() (this=0x7f5ea40011c0)
    at ../../Source/WTF/wtf/Functional.h:405
#14 0x00007f5ebeaaaf4e in WTF::Function<void ()>::operator()() const (this=0x7f5ea4001ef0) at ../../Source/WTF/wtf/Functional.h:613
#15 0x00007f5ebf591ec5 in WebCore::RunLoop::performWork (this=0x20fbef0) at ../../Source/WebCore/platform/RunLoop.cpp:67
#16 0x00007f5ebff943b6 in WebCore::RunLoop::queueWork (runLoop=0x20fbef0) at ../../Source/WebCore/platform/gtk/RunLoopGtk.cpp:102
#17 0x00007f5eb818ac9a in g_main_dispatch (context=0x1fed470) at /build/buildd/glib2.0-2.32.1/./glib/gmain.c:2515
#18 g_main_context_dispatch (context=0x1fed470) at /build/buildd/glib2.0-2.32.1/./glib/gmain.c:3052
#19 0x00007f5eb818b060 in g_main_context_iterate (dispatch=1, block=<optimized out>, context=0x1fed470, self=<optimized out>) at /build/buildd/glib2.0-2.32.1/./glib/gmain.c:3123
#20 g_main_context_iterate (context=0x1fed470, block=<optimized out>, dispatch=1, self=<optimized out>) at /build/buildd/glib2.0-2.32.1/./glib/gmain.c:3060
#21 0x00007f5eb818b45a in g_main_loop_run (loop=0x20fbf80) at /build/buildd/glib2.0-2.32.1/./glib/gmain.c:3317
#22 0x00007f5ebff94120 in WebCore::RunLoop::run () at ../../Source/WebCore/platform/gtk/RunLoopGtk.cpp:59
#23 0x00007f5ebec0487e in WebKit::WebProcessMainGtk (argc=2, argv=0x7fff5b919088) at ../../Source/WebKit2/WebProcess/gtk/WebProcessMainGtk.cpp:73
#24 0x0000000000400784 in main (argc=2, argv=0x7fff5b919088) at ../../Source/WebKit2/gtk/MainGtk.cpp:31
(gdb)

[Sudarsana Nagineni (babu)]

I think we should use deref() instead of delete to destroy the platformData
since the DataObjectGtk is inherited from RefCounted.

http://trac.webkit.org/browser/trunk/Source/WebKit2/WebProcess/WebPage/WebPage.cpp#L2183

[Sudarsana Nagineni (babu)]

Created attachment 144569 [details]
patch

Use deref() instead of delete to release refcounted DataObjectGtk.

[WebKit Review Bot]

Comment on attachment 144569 [details]
patch

Clearing flags on attachment: 144569

Committed r118796: <http://trac.webkit.org/changeset/118796>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.