Bug 299208 – [GTK] gdk_drop_status: assertion 'priv->state != GDK_DROP_STATE_FINISHED' failed

• Component: WebKitGTK
• Status: RESOLVED FIXED

[Michael Catanzaro]

Created attachment 476807 [details]
Full stack trace

I've encountered a fatal-criticals crash "gdk_drop_status: assertion 'priv->state != GDK_DROP_STATE_FINISHED' failed" during drag and drop using WebKitGTK 2.50.0. Haven't figured out how to reproduce it yet. For now, here's the stack trace:

#0  _g_log_abort (breakpoint=<optimized out>) at ../glib/gmessages.c:430
#1  g_logv
    (log_domain=0x7f5706c237a6 "Gdk", log_level=G_LOG_LEVEL_CRITICAL, format=<optimized out>, args=args@entry=0x7ffd6f1ac450) at ../glib/gmessages.c:1291
#2  0x00007f570730f7e3 in g_log (log_domain=<optimized out>, log_level=<optimized out>, format=<optimized out>)
    at ../glib/gmessages.c:1333
#3  0x00007f57019421dc in WebKit::WebPageProxy::didPerformDragControllerAction
    (this=<optimized out>, dragOperation=Python Exception <class 'gdb.error'>: value has been optimized out
..., dragHandlingMethod=<optimized out>, mouseIsOverFileInput=<optimized out>, numberOfItemsToBeAccepted=<optimized out>, insertionRect=..., editableElementRect=...)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WebKit/UIProcess/WebPageProxy.cpp:3835
#4  0x00007f5701985935 in WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0::operator()(std::optional<WebCore::DragOperation>, WebCore::DragHandlingMethod, bool, unsigned int, WebCore::IntRect const&, WebCore::IntRect const&, std::optional<WebCore::RemoteUserInputEventData>)
    (this=0x7f56efdc0b88, dragOperation=std::optional [no contained value], dragHandlingMethod=<optimized out>, mouseIsOverFileInput=false, numberOfItemsToBeAccepted=1, insertionRect=..., editableElementRect=..., remoteUserInputEventData=Python Exception <class 'gdb.error'>: value has been optimized out
...) at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WebKit/UIProcess/WebPageProxy.cpp:3795
#5  std::__invoke_impl<void, WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0, std::optional<WebCore::DragOperation>, WebCore::DragHandlingMethod, bool, unsigned int, WebCore::IntRect, WebCore::IntRect, std::optional<WebCore::RemoteUserInputEventData> >(std::__invoke_other, WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0&&, std::optional<WebCore::DragOperation>&&, WebCore::DragHandlingMethod&&, bool&&, unsigned int&&, WebCore::IntRect&&, WebCore::IntRect&&, std::optional<WebCore::RemoteUserInputEventData>&&)
    (__f=..., __args=..., __args=@0x7ffd6f1ac59d: WebCore::DragHandlingMethod::None, __args=@0x7ffd6f1ac59c: false, __args=@0x7ffd6f1ac598: 0, __args=..., __args=..., __args=...)
    at /usr/bin/../lib/gcc/x86_64-unknown-linux-gnu/15.2.0/../../../../include/c++/15.2.0/bits/invoke.h:63
#6  std::__invoke<WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0, std::optional<WebCore::DragOperation>, WebCore::DragHandlingMethod, bool, unsigned int, WebCore::IntRect, WebCore::IntRect, std::optional<WebCore::RemoteUserInputEventData> >(WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0&&, std::optional<WebCore::DragOperation>&&, WebCore::DragHandlingMethod&&, bool&&, unsigned int&&, WebCore::IntRect&&, WebCore::IntRect&&, std::optional<WebCore::RemoteUserInputEventData>&&)
    (__fn=..., __args=..., __args=@0x7ffd6f1ac59d: WebCore::DragHandlingMethod::None, __args=@0x7ffd6f1ac59c: false, __args=@0x7ffd6f1ac598: 0, __args=..., __args=..., __args=...)
    at /usr/bin/../lib/gcc/x86_64-unknown-linux-gnu/15.2.0/../../../../include/c++/15.2.0/bits/invoke.h:98
#7  std::__apply_impl<WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0, std::tuple<std::optional<WebCore::DragOperation>, WebCore::DragHandlingMethod, bool, unsigned int, WebCore::IntRect, WebCore::IntRect, std::optional<WebCore::RemoteUserInputEventData> >, 0ul, 1ul, 2ul, 3ul, 4ul, 5ul, 6ul>(WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0&&, std::tuple<std::o--Type <RET> for more, q to quit, c to continue without paging--c
ptional<WebCore::DragOperation>, WebCore::DragHandlingMethod, bool, unsigned int, WebCore::IntRect, WebCore::IntRect, std::optional<WebCore::RemoteUserInputEventData> >&&, std::integer_sequence<unsigned long, 0ul, 1ul, 2ul, 3ul, 4ul, 5ul, 6ul>) (__f=..., __t=...)
    at /usr/bin/../lib/gcc/x86_64-unknown-linux-gnu/15.2.0/../../../../include/c++/15.2.0/tuple:2920
#8  apply<(lambda at /buildstream/gnome/sdk/webkitgtk-6.0.bst/Source/WebKit/UIProcess/WebPageProxy.cpp:3790:30), std::tuple<std::optional<WebCore::DragOperation>, WebCore::DragHandlingMethod, bool, unsigned int, WebCore::IntRect, WebCore::IntRect, std::optional<WebCore::RemoteUserInputEventData> > > (__f=..., __t=...)
    at /usr/bin/../lib/gcc/x86_64-unknown-linux-gnu/15.2.0/../../../../include/c++/15.2.0/tuple:2935
#9  IPC::Connection::callReply<Messages::WebPage::PerformDragControllerAction, WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0>(IPC::Connection*, IPC::Decoder&, WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0&&)
    (decoder=..., completionHandler=..., connection=<optimized out>)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WebKit/Platform/IPC/Connection.h:1034
#10 IPC::Connection::makeAsyncReplyCompletionHandler<Messages::WebPage::PerformDragControllerAction, WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0>(WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0&&, WTF::ThreadLikeAssertion)::{lambda(IPC::Connection*, IPC::Decoder*)#1}::operator()(IPC::Connection*, IPC::Decoder*)
    (decoder=0x7f54e50f05a0, this=<optimized out>, connection=<optimized out>)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WebKit/Platform/IPC/Connection.h:945
#11 WTF::Detail::CallableWrapper<IPC::Connection::makeAsyncReplyCompletionHandler<Messages::WebPage::PerformDragControllerAction, WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0>(WebKit::WebPageProxy::performDragControllerAction(WebKit::DragControllerAction, WebCore::DragData&, std::optional<WTF::ObjectIdentifierGeneric<WebCore::FrameIdentifierType, WTF::ObjectIdentifierMainThreadAccessTraits<unsigned long>, unsigned long> > const&)::$_0&&, WTF::ThreadLikeAssertion)::{lambda(IPC::Connection*, IPC::Decoder*)#1}, void, IPC::Connection*, IPC::Decoder*>::call(IPC::Connection*, IPC::Decoder*) (this=0x7f56efdc0b80, in=<optimized out>, in=0x7f54e50f05a0) at WTF/Headers/wtf/Function.h:53
#12 0x00007f57018d75bf in WTF::Function<void(IPC::Connection*, IPC::Decoder*)>::operator()
    (in=0x0, in=0x1, this=<optimized out>) at WTF/Headers/wtf/Function.h:82
#13 WTF::CompletionHandler<void(IPC::Connection*, IPC::Decoder*)>::operator()
    (this=<optimized out>, in=0x0, in=0x1) at WTF/Headers/wtf/CompletionHandler.h:79
#14 WebKit::AuxiliaryProcessProxy::sendMessage(WTF::UniqueRef<IPC::Encoder>&&, WTF::OptionSet<IPC::SendOption>, std::optional<IPC::ConnectionAsyncReplyHandler>, WebKit::AuxiliaryProcessProxy::ShouldStartProcessThrottlerActivity)::$_1::operator()(IPC::Connection*, IPC::Decoder*) (this=<optimized out>, connection=0x0, decoder=0x1)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WebKit/UIProcess/AuxiliaryProcessProxy.cpp:263
#15 WTF::Detail::CallableWrapper<WebKit::AuxiliaryProcessProxy::sendMessage(WTF::UniqueRef<IPC::Encoder>&&, WTF::OptionSet<IPC::SendOption>, std::optional<IPC::ConnectionAsyncReplyHandler>, WebKit::AuxiliaryProcessProxy::ShouldStartProcessThrottlerActivity)::$_1, void, IPC::Connection*, IPC::Decoder*>::call
    (this=<optimized out>, in=0x0, in=0x1) at WTF/Headers/wtf/Function.h:53
#16 0x00007f570188835b in WTF::Function<void(IPC::Connection*, IPC::Decoder*)>::operator()
    (in=0x7f56efddc4e0, in=0x7f54e50f05a0, this=<optimized out>) at WTF/Headers/wtf/Function.h:82
#17 WTF::CompletionHandler<void(IPC::Connection*, IPC::Decoder*)>::operator()
    (this=0x7ffd6f1ac608, in=0x7f56efddc4e0, in=0x7f54e50f05a0) at WTF/Headers/wtf/CompletionHandler.h:79
#18 IPC::Connection::dispatchMessage (this=0x7f56efddc4e0, decoder=...)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WebKit/Platform/IPC/Connection.cpp:1365
#19 0x00007f5701888517 in IPC::Connection::dispatchMessage (this=0x7f56efddc4e0, message=...)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WebKit/Platform/IPC/Connection.cpp:1433
#20 0x00007f570188899d in IPC::Connection::dispatchIncomingMessages (this=0x7f56efddc4e0)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WebKit/Platform/IPC/Connection.cpp:1557
#21 0x00007f57004823a5 in WTF::Function<void()>::operator() (this=0x7ffd6f1ac720)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WTF/wtf/Function.h:82
#22 WTF::RunLoop::performWork (this=0x7f56ef008180)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WTF/wtf/RunLoop.cpp:148
#23 0x00007f570054187d in WTF::RunLoop::RunLoop()::$_0::operator()(void*) const (userData=0x1, 
    userData@entry=0x7f56ef008180, this=<optimized out>)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WTF/wtf/glib/RunLoopGLib.cpp:80
#24 WTF::RunLoop::RunLoop()::$_0::__invoke(void*) (userData=0x1)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WTF/wtf/glib/RunLoopGLib.cpp:79
#25 0x00007f57005409a1 in WTF::RunLoop::$_0::operator()
    (source=0x55f0de78f900, callback=0x7f5700541870 <WTF::RunLoop::RunLoop()::$_0::__invoke(void*)>, userData=0x7f56ef008180, this=<optimized out>)
    at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WTF/wtf/glib/RunLoopGLib.cpp:53
#26 WTF::RunLoop::$_0::__invoke
    (source=0x55f0de78f900, callback=0x7f5700541870 <WTF::RunLoop::RunLoop()::$_0::__invoke(void*)>, userData=0x7f56ef008180) at /usr/lib/debug/source/sdk/webkitgtk-6.0.bst/Source/WTF/wtf/glib/RunLoopGLib.cpp:45
#27 0x00007f57073027cb in g_main_dispatch (context=context@entry=0x55f0de74cd10) at ../glib/gmain.c:3565
#28 0x00007f5707305c07 in g_main_context_dispatch_unlocked (context=0x55f0de74cd10) at ../glib/gmain.c:4425
#29 g_main_context_iterate_unlocked
    (context=context@entry=0x55f0de74cd10, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at ../glib/gmain.c:4490
#30 0x00007f5707306453 in g_main_context_iteration
    (context=context@entry=0x55f0de74cd10, may_block=may_block@entry=1) at ../glib/gmain.c:4556
#31 0x00007f57074fe98d in g_application_run
    (application=0x55f0de78d570 [EphyShell], argc=<optimized out>, argv=<optimized out>)
    at ../gio/gapplication.c:2741
#32 0x000055f0d147c022 in main (argc=<optimized out>, argv=<optimized out>) at ../src/ephy-main.c:454

I'll attach a full stack trace.

[Michael Catanzaro]

So the crash is actually in DropTarget::didPerformAction (in DropTargetGtk4.cpp) which confusingly does not appear in the stack trace, due to optimization I guess.

The assertion dates back to https://gitlab.gnome.org/GNOME/gtk/-/commit/5a726bc6656d543f9a0d02e38b2ae76d60f52390 so it must be a WebKit regression.

[Michael Catanzaro]

Found a reproducer! Drag the URL in the comment above into the comment box below on this bug (if you are logged in). It's probably bisectable. I will investigate.

Also works with dragging URLs in Slack conversations into anywhere on Slack.

[Michael Catanzaro]

Unfortunately it only crashes in Epiphany Tech Preview. When building the same WebKitGTK version (2.50.0) myself, no crash. So much for my plan to bisect it. :(

[Michael Catanzaro]

Matthias says: "it happens if you try to read a value from the GdkDrop after declaring the drop finished"

[Michael Catanzaro]

Added some debugging in DropTargetGtk4.cpp. What happens outside of Flatpak is:

 * DropTarget::enter is called twice. Second time is probably a bug.
 * DropTarget::didPerformAction gets called a few dozen times.
 * DropTarget::drop gets called once, completing the drop. It's a bug to call gdk_drop_status() after this point.
 * DropTarget::leave gets called once.
 * DropTarget::didPerformAction gets called twice more.

and everything works fine. Notably, DropTarget::leave unsets m_drop and will cause DropTarget::didPerformAction to bail without ever calling gdk_drop_status().

So my guess is that under Flatpak, instead of drop -> leave -> didPerformAction, we have drop -> didPerformAction -> leave, which would crash. However, I'm not sure because testing anything under flatpak is a tremendous pain.

[Angelo Schirinzi]

*** Bug 302405 has been marked as a duplicate of this bug. ***

[Hyland B. (swagtoy)]

Also reproducible if you drag a file/folder from nautilus.

[Hyland B. (swagtoy)]

Just throwing a guess, I wonder if it's related to bwrap or anything? You did mention flatpak specifically, after all.

[Michael Catanzaro]

Surprisingly, the reproducer in bug #271957 triggers this crash even outside Flatpak.

(In reply to Hyland B. (swagtoy) from comment #8)
> Just throwing a guess, I wonder if it's related to bwrap or anything? You
> did mention flatpak specifically, after all.

I was thinking it's likely going to be related to how WebKit uses the file transfer portal, but that was before I saw the non-Flatpak reproducer.

[Michael Catanzaro]

(In reply to Michael Catanzaro from comment #9)
> Surprisingly, the reproducer in bug #271957 triggers this crash even outside
> Flatpak.

OK, this is expected because what I'm doing is dragging a file or folder from nautilus. And you just told me about this a few comments up.

That was *extremely* helpful information, which I completely ignored. :P

[Hyland B. (swagtoy)]

Pretty much dragging anything will crash it ;-/ I think the logic is just broken entirely.

[Michael Catanzaro]

Pull request: https://github.com/WebKit/WebKit/pull/54348

[Michael Catanzaro]

*** Bug 303004 has been marked as a duplicate of this bug. ***

[EWS]

Committed 303500@main (5a5eb476f8e3): <https://commits.webkit.org/303500@main>

Reviewed commits have been landed. Closing PR #54348 and removing active labels.