assertion found while fuzzing REV 64b0835fd507 OS|Linux|0.0.0 Linux 4.13.0-32-generic #35~16.04.1-Ubuntu SMP Thu Jan 25 10:13:43 UTC 2018 x86_64 CPU|amd64|family 6 model 94 stepping 3|1 GPU||| Crash|SIGSEGV|0x0|0 0|0|libxul.so|mozilla::VerifyFlatTree|hg:hg.mozilla.org/mozilla-central:layout/base/ServoRestyleManager.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|1251|0x18 0|1|libxul.so|mozilla::VerifyFlatTree|hg:hg.mozilla.org/mozilla-central:layout/base/ServoRestyleManager.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|1252|0x8 0|2|libxul.so|mozilla::ServoRestyleManager::ProcessPendingRestyles|hg:hg.mozilla.org/mozilla-central:layout/base/ServoRestyleManager.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|1262|0x8 0|3|libxul.so|mozilla::PresShell::DoFlushPendingNotifications|hg:hg.mozilla.org/mozilla-central:layout/base/PresShell.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|4209|0x18 0|4|libxul.so|nsRefreshDriver::Tick|hg:hg.mozilla.org/mozilla-central:layout/base/nsRefreshDriver.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|1915|0x5 0|5|libxul.so|mozilla::RefreshDriverTimer::TickRefreshDrivers|hg:hg.mozilla.org/mozilla-central:layout/base/nsRefreshDriver.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|310|0xf 0|6|libxul.so|mozilla::RefreshDriverTimer::Tick|hg:hg.mozilla.org/mozilla-central:layout/base/nsRefreshDriver.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|332|0x12 0|7|libxul.so|mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::TickRefreshDriver|hg:hg.mozilla.org/mozilla-central:layout/base/nsRefreshDriver.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|773|0x5 0|8|libxul.so|mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyVsync|hg:hg.mozilla.org/mozilla-central:layout/base/nsRefreshDriver.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|587|0xc 0|9|libxul.so|mozilla::layout::VsyncChild::RecvNotify|hg:hg.mozilla.org/mozilla-central:layout/ipc/VsyncChild.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|68|0x9 0|10|libxul.so|mozilla::layout::PVsyncChild::OnMessageReceived|s3:gecko-generated-sources:06086093ccb59dd5a99cf8c9f9fb7f4860fd8ddbfd516af5e5b3508be62029679421dcf2abdf6b1c945b6a054050bd403c9574aad49f857cb4a31d3f4cf56b9a/ipc/ipdl/PVsyncChild.cpp:|155|0xf 0|11|libxul.so|mozilla::ipc::MessageChannel::DispatchAsyncMessage|hg:hg.mozilla.org/mozilla-central:ipc/glue/MessageChannel.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|2110|0x6 0|12|libxul.so|mozilla::ipc::MessageChannel::DispatchMessage|hg:hg.mozilla.org/mozilla-central:ipc/glue/MessageChannel.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|2040|0xb 0|13|libxul.so|mozilla::ipc::MessageChannel::RunMessage|hg:hg.mozilla.org/mozilla-central:ipc/glue/MessageChannel.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|1886|0xb 0|14|libxul.so|mozilla::ipc::MessageChannel::MessageTask::Run|hg:hg.mozilla.org/mozilla-central:ipc/glue/MessageChannel.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|1919|0xc 0|15|libxul.so|nsThread::ProcessNextEvent|hg:hg.mozilla.org/mozilla-central:xpcom/threads/nsThread.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|1040|0x15 0|16|libxul.so|NS_ProcessNextEvent|hg:hg.mozilla.org/mozilla-central:xpcom/threads/nsThreadUtils.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|517|0x11 0|17|libxul.so|mozilla::ipc::MessagePump::Run|hg:hg.mozilla.org/mozilla-central:ipc/glue/MessagePump.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|97|0xa 0|18|libxul.so|MessageLoop::RunInternal|hg:hg.mozilla.org/mozilla-central:ipc/chromium/src/base/message_loop.cc:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|326|0x17 0|19|libxul.so|MessageLoop::Run|hg:hg.mozilla.org/mozilla-central:ipc/chromium/src/base/message_loop.cc:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|319|0x8 0|20|libxul.so|nsBaseAppShell::Run|hg:hg.mozilla.org/mozilla-central:widget/nsBaseAppShell.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|157|0xd 0|21|libxul.so|XRE_RunAppShell|hg:hg.mozilla.org/mozilla-central:toolkit/xre/nsEmbedFunctions.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|892|0x11 0|22|libxul.so|mozilla::ipc::MessagePumpForChildProcess::Run|hg:hg.mozilla.org/mozilla-central:ipc/glue/MessagePump.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|269|0x5 0|23|libxul.so|MessageLoop::RunInternal|hg:hg.mozilla.org/mozilla-central:ipc/chromium/src/base/message_loop.cc:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|326|0x17 0|24|libxul.so|MessageLoop::Run|hg:hg.mozilla.org/mozilla-central:ipc/chromium/src/base/message_loop.cc:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|319|0x8 0|25|libxul.so|XRE_InitChildProcess|hg:hg.mozilla.org/mozilla-central:toolkit/xre/nsEmbedFunctions.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|718|0x8 0|26|firefox|content_process_main|hg:hg.mozilla.org/mozilla-central:ipc/contentproc/plugin-container.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|63|0x14 0|27|firefox|main|hg:hg.mozilla.org/mozilla-central:browser/app/nsBrowserApp.cpp:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|280|0x11 0|28|libc-2.23.so||||0x20830 0|29|firefox|MOZ_ReportAssertionFailure|hg:hg.mozilla.org/mozilla-central:mfbt/Assertions.h:64b0835fd507bb7a6884c4dcd0bb33d5b9291ca9|164|0x5

Comment on attachment 8953722 <html> <head> <script> try { o1 = document.createElement('textarea') } catch(e) { } try { document.documentElement.appendChild(o1) } catch(e) { } try { o2 = document.createElementNS("", "a") } catch(e) { } try { o3 = o1.insertAdjacentElement("afterbegin", o2) } catch(e) { } try { o4 = o1.createShadowRoot() } catch(e) { } </script> </head> </html>

Comment on attachment 8953722 <html> <head> <script> try { o1 = document.createElement('textarea') } catch(e) { } try { document.documentElement.appendChild(o1) } catch(e) { } try { o2 = document.createElementNS("", "a") } catch(e) { } try { o3 = o1.insertAdjacentElement("afterbegin", o2) } catch(e) { } try { o4 = o1.createShadowRoot() } catch(e) { } </script> </head> </html>

Please ignore the weirdness. I accidentally attached the wrong test case and was trying to remove it.

This is creating a Shadow Root in a <textarea> using the Shadow DOM v0 API, which we're not going to ship. Could fuzzers be changed to use attachShadow({ mode: "open" }) instead?

the fuzzers were changed as per jkratzer.