Assertion failure: mFlushState == eNotFlushing (Tried to run script while flushing.), at src/parser/html/nsHtml5TreeOpExecutor.cpp:729 #0 nsHtml5TreeOpExecutor::RunScript(nsIContent*) src/obj-firefox/dist/include/nsIScriptElement.h:180:20 #1 nsHtml5TreeOperation::Perform(nsHtml5TreeOpExecutor*, nsIContent**, bool*, bool*) src/parser/html/nsHtml5TreeOperation.cpp:973:17 #2 nsHtml5TreeOpExecutor::RunFlushLoop() src/parser/html/nsHtml5TreeOpExecutor.cpp:489:17 #3 nsHtml5ExecutorFlusher::Run() src/parser/html/nsHtml5StreamParser.cpp:121:18 #4 mozilla::SchedulerGroup::Runnable::Run() src/xpcom/threads/SchedulerGroup.cpp:337:32 #5 nsThread::ProcessNextEvent(bool, bool*) src/xpcom/threads/nsThread.cpp:1166:14 #6 NS_ProcessNextEvent(nsIThread*, bool) src/xpcom/threads/nsThreadUtils.cpp:519:10 #7 mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) src/ipc/glue/MessagePump.cpp:125:5 #8 RunInternal src/ipc/chromium/src/base/message_loop.cc:325:10 #9 RunHandler src/ipc/chromium/src/base/message_loop.cc:318 #10 MessageLoop::Run() src/ipc/chromium/src/base/message_loop.cc:298 #11 nsBaseAppShell::Run() src/widget/nsBaseAppShell.cpp:158:27 #12 XRE_RunAppShell() src/toolkit/xre/nsEmbedFunctions.cpp:938:22 #13 RunInternal src/ipc/chromium/src/base/message_loop.cc:325:10 #14 RunHandler src/ipc/chromium/src/base/message_loop.cc:318 #15 MessageLoop::Run() src/ipc/chromium/src/base/message_loop.cc:298 #16 XRE_InitChildProcess(int, char**, XREChildData const*) src/toolkit/xre/nsEmbedFunctions.cpp:764:34 #17 content_process_main src/browser/app/../../ipc/contentproc/plugin-container.cpp:50:30 #18 main src/browser/app/nsBrowserApp.cpp:287 #19 __libc_start_main /build/glibc-Cl5G7W/glibc-2.23/csu/../csu/libc-start.c:291 #20 _start (firefox+0x4216b8)

Henri, I'm setting this to P3, but feel free to adjust based on your deeper understanding of this code when you get back :-)

Hmm. Can't repro in local debug build but can repro in Nightly...

Can't repro in a local opt build, either.