Version-Release number of selected component:
webkitgtk4-2.8.5-1.fc22

Additional info:
reporter:       libreport-2.6.2
backtrace_rating: 4
cmdline:        /usr/libexec/webkit2gtk-4.0/WebKitWebProcess 27
crash_function: __pthread_mutex_lock
executable:     /usr/libexec/webkit2gtk-4.0/WebKitWebProcess
global_pid:     9647
kernel:         4.1.5-200.fc22.x86_64
runlevel:       N 5
type:           CCpp
uid:            1000

Truncated backtrace:
Thread no. 1 (10 frames)
 #0 __pthread_mutex_lock at ../nptl/pthread_mutex_lock.c:67
 #1 IPC::Connection::SyncMessageState::dispatchMessages(IPC::Connection*) at /lib64/libwebkit2gtk-4.0.so.37
 #2 IPC::Connection::waitForSyncReply(unsigned long, std::chrono::duration<long, std::ratio<1l, 1000l> >, unsigned int) at /lib64/libwebkit2gtk-4.0.so.37
 #3 IPC::Connection::sendSyncMessage(unsigned long, std::unique_ptr<IPC::MessageEncoder, std::default_delete<IPC::MessageEncoder> >, std::chrono::duration<long, std::ratio<1l, 1000l> >, unsigned int) at /lib64/libwebkit2gtk-4.0.so.37
 #4 bool IPC::Connection::sendSync<Messages::WebProcessProxy::GetPluginProcessConnection>(Messages::WebProcessProxy::GetPluginProcessConnection&&, Messages::WebProcessProxy::GetPluginProcessConnection::Reply&&, unsigned long, std::chrono::duration<long, std::ratio<1l, 1000l> >, unsigned int) at /lib64/libwebkit2gtk-4.0.so.37
 #5 WebKit::PluginProcessConnectionManager::getPluginProcessConnection(unsigned long) at /lib64/libwebkit2gtk-4.0.so.37
 #6 WebKit::PluginProxy::initialize(WebKit::Plugin::Parameters const&) at /lib64/libwebkit2gtk-4.0.so.37
 #7 WebCore::ScrollView::addChild(WTF::PassRefPtr<WebCore::Widget>) at /lib64/libwebkit2gtk-4.0.so.37
 #8 WebCore::WidgetHierarchyUpdatesSuspensionScope::moveWidgets() at /lib64/libwebkit2gtk-4.0.so.37
 #9 WebCore::FrameView::updateEmbeddedObjects() at /lib64/libwebkit2gtk-4.0.so.37