Bug 1427792 Comment 16 Edit History

Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.

Testcase found while fuzzing mozilla-central rev f4ad9b76e5f8 (built with: --enable-debug --enable-fuzzing).

Testcase can be reproduced using the following commands:
```
$ pip install fuzzfetch grizzly-framework
$ python -m fuzzfetch --build f4ad9b76e5f8 --debug --fuzzing -n firefox
$ python -m grizzly.replay ./firefox/firefox testcase.zip
```

```
Assertion failure: IsAncestor(aOne, aTwo) || IsAncestor(aTwo, aOne), at /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275

    ==784958==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7feee64f375f bp 0x7ffe5b82ac60 sp 0x7ffe5b82abb0 T784958)
    ==784958==The signal is caused by a WRITE memory access.
    ==784958==Hint: address points to the zero page.
        #0 0x7feee64f375f in PickDescendant /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275:5
        #1 0x7feee64f375f in mozilla::layers::ClipManager::SwitchItem(mozilla::nsDisplayItem*) /gfx/layers/wr/ClipManager.cpp:215:19
        #2 0x7feee65323ae in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1782:43
        #3 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #4 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #5 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #6 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #7 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #8 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #9 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #10 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #11 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #12 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #13 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #14 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #15 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #16 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #17 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #18 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #19 0x7feee9d5ff97 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #20 0x7feee9d5ff97 in mozilla::nsDisplayOwnLayer::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:5714:22
        #21 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #22 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #23 0x7feee653138d in mozilla::layers::WebRenderCommandBuilder::BuildWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::nsDisplayList*, mozilla::nsDisplayListBuilder*, mozilla::layers::WebRenderScrollData&, WrFiltersHolder&&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1601:5
        #24 0x7feee6544326 in mozilla::layers::WebRenderLayerManager::EndTransactionWithoutLayer(mozilla::nsDisplayList*, mozilla::nsDisplayListBuilder*, WrFiltersHolder&&, mozilla::layers::WebRenderBackgroundData*, double) /gfx/layers/wr/WebRenderLayerManager.cpp:371:30
        #25 0x7feee9d4d4b5 in mozilla::nsDisplayList::PaintRoot(mozilla::nsDisplayListBuilder*, gfxContext*, unsigned int, mozilla::Maybe<double>) /layout/painting/nsDisplayList.cpp:2414:18
        #26 0x7feee99b6d32 in nsLayoutUtils::PaintFrame(gfxContext*, nsIFrame*, nsRegion const&, unsigned int, mozilla::nsDisplayListBuilderMode, nsLayoutUtils::PaintFrameFlags) /layout/base/nsLayoutUtils.cpp:3493:45
        #27 0x7feee992a175 in mozilla::PresShell::Paint(nsView*, nsRegion const&, mozilla::PaintFlags) /layout/base/PresShell.cpp:6360:5
        #28 0x7feee959a92e in nsViewManager::ProcessPendingUpdatesPaint(nsIWidget*) /view/nsViewManager.cpp:467:18
        #29 0x7feee959a44b in nsViewManager::ProcessPendingUpdatesForView(nsView*, bool) /view/nsViewManager.cpp:402:22
        #30 0x7feee959ba2f in nsViewManager::ProcessPendingUpdates() /view/nsViewManager.cpp:980:5
        #31 0x7feee98e73ca in nsRefreshDriver::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsRefreshDriver::IsExtraTick) /layout/base/nsRefreshDriver.cpp:2505:11
        #32 0x7feee98ee69a in TickDriver /layout/base/nsRefreshDriver.cpp:348:13
        #33 0x7feee98ee69a in mozilla::RefreshDriverTimer::TickRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsTArray<RefPtr<nsRefreshDriver> >&) /layout/base/nsRefreshDriver.cpp:326:7
        #34 0x7feee98ee5b3 in mozilla::RefreshDriverTimer::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:342:5
        #35 0x7feee98ee480 in mozilla::VsyncRefreshDriverTimer::RunRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:771:5
        #36 0x7feee98edb1a in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::TickRefreshDriver(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:700:16
        #37 0x7feee98ed435 in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyParentProcessVsync() /layout/base/nsRefreshDriver.cpp:617:7
        #38 0x7feee98eceb9 in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyVsync(mozilla::VsyncEvent const&) /layout/base/nsRefreshDriver.cpp:538:9
        #39 0x7feee90b3f26 in mozilla::dom::VsyncChild::RecvNotify(mozilla::VsyncEvent const&, float const&) /dom/ipc/VsyncChild.cpp:68:15
        #40 0x7feee5cd47e4 in mozilla::dom::PVsyncChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PVsyncChild.cpp:178:54
        #41 0x7feee5aa902c in mozilla::ipc::PBackgroundChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PBackgroundChild.cpp:6091:32
        #42 0x7feee573730f in mozilla::ipc::MessageChannel::DispatchAsyncMessage(mozilla::ipc::ActorLifecycleProxy*, IPC::Message const&) /ipc/glue/MessageChannel.cpp:2053:25
        #43 0x7feee5733e21 in mozilla::ipc::MessageChannel::DispatchMessage(IPC::Message&&) /ipc/glue/MessageChannel.cpp:1978:9
        #44 0x7feee57352a5 in mozilla::ipc::MessageChannel::RunMessage(mozilla::ipc::MessageChannel::MessageTask&) /ipc/glue/MessageChannel.cpp:1826:3
        #45 0x7feee5735e3b in mozilla::ipc::MessageChannel::MessageTask::Run() /ipc/glue/MessageChannel.cpp:1857:13
        #46 0x7feee4cf983e in mozilla::RunnableTask::Run() /xpcom/threads/TaskController.cpp:502:16
        #47 0x7feee4cd4b0f in mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /xpcom/threads/TaskController.cpp:805:26
        #48 0x7feee4cd3778 in mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /xpcom/threads/TaskController.cpp:641:15
        #49 0x7feee4cd39f3 in mozilla::TaskController::ProcessPendingMTTask(bool) /xpcom/threads/TaskController.cpp:425:36
        #50 0x7feee4cfcea9 in operator() /xpcom/threads/TaskController.cpp:138:37
        #51 0x7feee4cfcea9 in mozilla::detail::RunnableFunction<mozilla::TaskController::InitializeInternal()::$_1>::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:531:5
        #52 0x7feee4ce82ef in nsThread::ProcessNextEvent(bool, bool*) /xpcom/threads/nsThread.cpp:1148:16
        #53 0x7feee4cef03a in NS_ProcessNextEvent(nsIThread*, bool) /xpcom/threads/nsThreadUtils.cpp:466:10
        #54 0x7feee573d124 in mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) /ipc/glue/MessagePump.cpp:107:5
        #55 0x7feee565d867 in MessageLoop::RunInternal() /ipc/chromium/src/base/message_loop.cc:331:10
        #56 0x7feee565d772 in RunHandler /ipc/chromium/src/base/message_loop.cc:324:3
        #57 0x7feee565d772 in MessageLoop::Run() /ipc/chromium/src/base/message_loop.cc:306:3
        #58 0x7feee95ec6c8 in nsBaseAppShell::Run() /widget/nsBaseAppShell.cpp:137:27
        #59 0x7feeeb46cf33 in XRE_RunAppShell() /toolkit/xre/nsEmbedFunctions.cpp:917:20
        #60 0x7feee573e06a in mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) /ipc/glue/MessagePump.cpp:235:9
        #61 0x7feee565d867 in MessageLoop::RunInternal() /ipc/chromium/src/base/message_loop.cc:331:10
        #62 0x7feee565d772 in RunHandler /ipc/chromium/src/base/message_loop.cc:324:3
        #63 0x7feee565d772 in MessageLoop::Run() /ipc/chromium/src/base/message_loop.cc:306:3
        #64 0x7feeeb46c56e in XRE_InitChildProcess(int, char**, XREChildData const*) /toolkit/xre/nsEmbedFunctions.cpp:749:34
        #65 0x55c80051dab6 in content_process_main /browser/app/../../ipc/contentproc/plugin-container.cpp:57:28
        #66 0x55c80051dab6 in main /browser/app/nsBrowserApp.cpp:327:18
        #67 0x7feefa4b30b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
        #68 0x55c8004fa8bc in _start (/home/jkratzer/builds/mc-debug/firefox-bin+0x158bc)
    
    UndefinedBehaviorSanitizer can not provide additional info.
    SUMMARY: UndefinedBehaviorSanitizer: SEGV /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275:5 in PickDescendant
    ==784958==ABORTING
```
Testcase found while fuzzing mozilla-central rev f4ad9b76e5f8 (built with: --enable-debug --enable-fuzzing).

Testcase can be reproduced using the following commands:
```
$ pip install fuzzfetch grizzly-framework
$ python -m fuzzfetch --build f4ad9b76e5f8 --debug --fuzzing -n firefox
$ python -m grizzly.replay ./firefox/firefox testcase.zip
```

```
Assertion failure: IsAncestor(aOne, aTwo) || IsAncestor(aTwo, aOne), at /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275

    ==784958==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7feee64f375f bp 0x7ffe5b82ac60 sp 0x7ffe5b82abb0 T784958)
    ==784958==The signal is caused by a WRITE memory access.
    ==784958==Hint: address points to the zero page.
        #0 0x7feee64f375f in PickDescendant /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275:5
        #1 0x7feee64f375f in mozilla::layers::ClipManager::SwitchItem(mozilla::nsDisplayItem*) /gfx/layers/wr/ClipManager.cpp:215:19
        #2 0x7feee65323ae in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1782:43
        #3 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #4 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #5 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #6 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #7 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #8 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #9 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #10 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #11 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #12 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #13 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #14 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #15 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #16 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #17 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #18 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #19 0x7feee9d5ff97 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #20 0x7feee9d5ff97 in mozilla::nsDisplayOwnLayer::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:5714:22
        #21 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #22 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #23 0x7feee653138d in mozilla::layers::WebRenderCommandBuilder::BuildWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::nsDisplayList*, mozilla::nsDisplayListBuilder*, mozilla::layers::WebRenderScrollData&, WrFiltersHolder&&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1601:5
        #24 0x7feee6544326 in mozilla::layers::WebRenderLayerManager::EndTransactionWithoutLayer(mozilla::nsDisplayList*, mozilla::nsDisplayListBuilder*, WrFiltersHolder&&, mozilla::layers::WebRenderBackgroundData*, double) /gfx/layers/wr/WebRenderLayerManager.cpp:371:30
        #25 0x7feee9d4d4b5 in mozilla::nsDisplayList::PaintRoot(mozilla::nsDisplayListBuilder*, gfxContext*, unsigned int, mozilla::Maybe<double>) /layout/painting/nsDisplayList.cpp:2414:18
        #26 0x7feee99b6d32 in nsLayoutUtils::PaintFrame(gfxContext*, nsIFrame*, nsRegion const&, unsigned int, mozilla::nsDisplayListBuilderMode, nsLayoutUtils::PaintFrameFlags) /layout/base/nsLayoutUtils.cpp:3493:45
        #27 0x7feee992a175 in mozilla::PresShell::Paint(nsView*, nsRegion const&, mozilla::PaintFlags) /layout/base/PresShell.cpp:6360:5
        #28 0x7feee959a92e in nsViewManager::ProcessPendingUpdatesPaint(nsIWidget*) /view/nsViewManager.cpp:467:18
        #29 0x7feee959a44b in nsViewManager::ProcessPendingUpdatesForView(nsView*, bool) /view/nsViewManager.cpp:402:22
        #30 0x7feee959ba2f in nsViewManager::ProcessPendingUpdates() /view/nsViewManager.cpp:980:5
        #31 0x7feee98e73ca in nsRefreshDriver::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsRefreshDriver::IsExtraTick) /layout/base/nsRefreshDriver.cpp:2505:11
        #32 0x7feee98ee69a in TickDriver /layout/base/nsRefreshDriver.cpp:348:13
        #33 0x7feee98ee69a in mozilla::RefreshDriverTimer::TickRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsTArray<RefPtr<nsRefreshDriver> >&) /layout/base/nsRefreshDriver.cpp:326:7
        #34 0x7feee98ee5b3 in mozilla::RefreshDriverTimer::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:342:5
        #35 0x7feee98ee480 in mozilla::VsyncRefreshDriverTimer::RunRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:771:5
        #36 0x7feee98edb1a in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::TickRefreshDriver(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:700:16
        #37 0x7feee98ed435 in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyParentProcessVsync() /layout/base/nsRefreshDriver.cpp:617:7
        #38 0x7feee98eceb9 in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyVsync(mozilla::VsyncEvent const&) /layout/base/nsRefreshDriver.cpp:538:9
        #39 0x7feee90b3f26 in mozilla::dom::VsyncChild::RecvNotify(mozilla::VsyncEvent const&, float const&) /dom/ipc/VsyncChild.cpp:68:15
        #40 0x7feee5cd47e4 in mozilla::dom::PVsyncChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PVsyncChild.cpp:178:54
        #41 0x7feee5aa902c in mozilla::ipc::PBackgroundChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PBackgroundChild.cpp:6091:32
        #42 0x7feee573730f in mozilla::ipc::MessageChannel::DispatchAsyncMessage(mozilla::ipc::ActorLifecycleProxy*, IPC::Message const&) /ipc/glue/MessageChannel.cpp:2053:25
        #43 0x7feee5733e21 in mozilla::ipc::MessageChannel::DispatchMessage(IPC::Message&&) /ipc/glue/MessageChannel.cpp:1978:9
        #44 0x7feee57352a5 in mozilla::ipc::MessageChannel::RunMessage(mozilla::ipc::MessageChannel::MessageTask&) /ipc/glue/MessageChannel.cpp:1826:3
        #45 0x7feee5735e3b in mozilla::ipc::MessageChannel::MessageTask::Run() /ipc/glue/MessageChannel.cpp:1857:13
        #46 0x7feee4cf983e in mozilla::RunnableTask::Run() /xpcom/threads/TaskController.cpp:502:16
        #47 0x7feee4cd4b0f in mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /xpcom/threads/TaskController.cpp:805:26
        #48 0x7feee4cd3778 in mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /xpcom/threads/TaskController.cpp:641:15
        #49 0x7feee4cd39f3 in mozilla::TaskController::ProcessPendingMTTask(bool) /xpcom/threads/TaskController.cpp:425:36
        #50 0x7feee4cfcea9 in operator() /xpcom/threads/TaskController.cpp:138:37
        #51 0x7feee4cfcea9 in mozilla::detail::RunnableFunction<mozilla::TaskController::InitializeInternal()::$_1>::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:531:5
        #52 0x7feee4ce82ef in nsThread::ProcessNextEvent(bool, bool*) /xpcom/threads/nsThread.cpp:1148:16
        #53 0x7feee4cef03a in NS_ProcessNextEvent(nsIThread*, bool) /xpcom/threads/nsThreadUtils.cpp:466:10
        #54 0x7feee573d124 in mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) /ipc/glue/MessagePump.cpp:107:5
        #55 0x7feee565d867 in MessageLoop::RunInternal() /ipc/chromium/src/base/message_loop.cc:331:10
        #56 0x7feee565d772 in RunHandler /ipc/chromium/src/base/message_loop.cc:324:3
        #57 0x7feee565d772 in MessageLoop::Run() /ipc/chromium/src/base/message_loop.cc:306:3
        #58 0x7feee95ec6c8 in nsBaseAppShell::Run() /widget/nsBaseAppShell.cpp:137:27
        #59 0x7feeeb46cf33 in XRE_RunAppShell() /toolkit/xre/nsEmbedFunctions.cpp:917:20
        #60 0x7feee573e06a in mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) /ipc/glue/MessagePump.cpp:235:9
        #61 0x7feee565d867 in MessageLoop::RunInternal() /ipc/chromium/src/base/message_loop.cc:331:10
        #62 0x7feee565d772 in RunHandler /ipc/chromium/src/base/message_loop.cc:324:3
        #63 0x7feee565d772 in MessageLoop::Run() /ipc/chromium/src/base/message_loop.cc:306:3
        #64 0x7feeeb46c56e in XRE_InitChildProcess(int, char**, XREChildData const*) /toolkit/xre/nsEmbedFunctions.cpp:749:34
        #65 0x55c80051dab6 in content_process_main /browser/app/../../ipc/contentproc/plugin-container.cpp:57:28
        #66 0x55c80051dab6 in main /browser/app/nsBrowserApp.cpp:327:18
        #67 0x7feefa4b30b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
        #68 0x55c8004fa8bc in _start (/home/jkratzer/builds/mc-debug/firefox-bin+0x158bc)
    
    UndefinedBehaviorSanitizer can not provide additional info.
    SUMMARY: UndefinedBehaviorSanitizer: SEGV /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275:5 in PickDescendant
    ==784958==ABORTING
Testcase found while fuzzing mozilla-central rev f4ad9b76e5f8 (built with: --enable-debug --enable-fuzzing).

Testcase can be reproduced using the following commands:
$ pip install fuzzfetch grizzly-framework
$ python -m fuzzfetch --build f4ad9b76e5f8 --debug --fuzzing -n firefox
$ python -m grizzly.replay ./firefox/firefox testcase.zip

```
Assertion failure: IsAncestor(aOne, aTwo) || IsAncestor(aTwo, aOne), at /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275
    ==784958==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7feee64f375f bp 0x7ffe5b82ac60 sp 0x7ffe5b82abb0 T784958)
    ==784958==The signal is caused by a WRITE memory access.
    ==784958==Hint: address points to the zero page.
        #0 0x7feee64f375f in PickDescendant /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275:5
        #1 0x7feee64f375f in mozilla::layers::ClipManager::SwitchItem(mozilla::nsDisplayItem*) /gfx/layers/wr/ClipManager.cpp:215:19
        #2 0x7feee65323ae in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1782:43
        #3 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #4 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #5 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #6 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #7 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #8 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #9 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #10 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #11 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #12 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #13 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #14 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #15 0x7feee9d708e9 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #16 0x7feee9d708e9 in mozilla::nsDisplayMasksAndClipPaths::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:8697:25
        #17 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #18 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #19 0x7feee9d5ff97 in CreateWebRenderCommands /layout/painting/nsDisplayList.cpp:5061:30
        #20 0x7feee9d5ff97 in mozilla::nsDisplayOwnLayer::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::layers::RenderRootStateManager*, mozilla::nsDisplayListBuilder*) /layout/painting/nsDisplayList.cpp:5714:22
        #21 0x7feee6533f82 in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommands(mozilla::nsDisplayItem*, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::layers::StackingContextHelper const&, mozilla::nsDisplayListBuilder*) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1681:41
        #22 0x7feee653264d in mozilla::layers::WebRenderCommandBuilder::CreateWebRenderCommandsFromDisplayList(mozilla::nsDisplayList*, mozilla::nsDisplayItem*, mozilla::nsDisplayListBuilder*, mozilla::layers::StackingContextHelper const&, mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1803:7
        #23 0x7feee653138d in mozilla::layers::WebRenderCommandBuilder::BuildWebRenderCommands(mozilla::wr::DisplayListBuilder&, mozilla::wr::IpcResourceUpdateQueue&, mozilla::nsDisplayList*, mozilla::nsDisplayListBuilder*, mozilla::layers::WebRenderScrollData&, WrFiltersHolder&&) /gfx/layers/wr/WebRenderCommandBuilder.cpp:1601:5
        #24 0x7feee6544326 in mozilla::layers::WebRenderLayerManager::EndTransactionWithoutLayer(mozilla::nsDisplayList*, mozilla::nsDisplayListBuilder*, WrFiltersHolder&&, mozilla::layers::WebRenderBackgroundData*, double) /gfx/layers/wr/WebRenderLayerManager.cpp:371:30
        #25 0x7feee9d4d4b5 in mozilla::nsDisplayList::PaintRoot(mozilla::nsDisplayListBuilder*, gfxContext*, unsigned int, mozilla::Maybe<double>) /layout/painting/nsDisplayList.cpp:2414:18
        #26 0x7feee99b6d32 in nsLayoutUtils::PaintFrame(gfxContext*, nsIFrame*, nsRegion const&, unsigned int, mozilla::nsDisplayListBuilderMode, nsLayoutUtils::PaintFrameFlags) /layout/base/nsLayoutUtils.cpp:3493:45
        #27 0x7feee992a175 in mozilla::PresShell::Paint(nsView*, nsRegion const&, mozilla::PaintFlags) /layout/base/PresShell.cpp:6360:5
        #28 0x7feee959a92e in nsViewManager::ProcessPendingUpdatesPaint(nsIWidget*) /view/nsViewManager.cpp:467:18
        #29 0x7feee959a44b in nsViewManager::ProcessPendingUpdatesForView(nsView*, bool) /view/nsViewManager.cpp:402:22
        #30 0x7feee959ba2f in nsViewManager::ProcessPendingUpdates() /view/nsViewManager.cpp:980:5
        #31 0x7feee98e73ca in nsRefreshDriver::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsRefreshDriver::IsExtraTick) /layout/base/nsRefreshDriver.cpp:2505:11
        #32 0x7feee98ee69a in TickDriver /layout/base/nsRefreshDriver.cpp:348:13
        #33 0x7feee98ee69a in mozilla::RefreshDriverTimer::TickRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsTArray<RefPtr<nsRefreshDriver> >&) /layout/base/nsRefreshDriver.cpp:326:7
        #34 0x7feee98ee5b3 in mozilla::RefreshDriverTimer::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:342:5
        #35 0x7feee98ee480 in mozilla::VsyncRefreshDriverTimer::RunRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:771:5
        #36 0x7feee98edb1a in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::TickRefreshDriver(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /layout/base/nsRefreshDriver.cpp:700:16
        #37 0x7feee98ed435 in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyParentProcessVsync() /layout/base/nsRefreshDriver.cpp:617:7
        #38 0x7feee98eceb9 in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyVsync(mozilla::VsyncEvent const&) /layout/base/nsRefreshDriver.cpp:538:9
        #39 0x7feee90b3f26 in mozilla::dom::VsyncChild::RecvNotify(mozilla::VsyncEvent const&, float const&) /dom/ipc/VsyncChild.cpp:68:15
        #40 0x7feee5cd47e4 in mozilla::dom::PVsyncChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PVsyncChild.cpp:178:54
        #41 0x7feee5aa902c in mozilla::ipc::PBackgroundChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PBackgroundChild.cpp:6091:32
        #42 0x7feee573730f in mozilla::ipc::MessageChannel::DispatchAsyncMessage(mozilla::ipc::ActorLifecycleProxy*, IPC::Message const&) /ipc/glue/MessageChannel.cpp:2053:25
        #43 0x7feee5733e21 in mozilla::ipc::MessageChannel::DispatchMessage(IPC::Message&&) /ipc/glue/MessageChannel.cpp:1978:9
        #44 0x7feee57352a5 in mozilla::ipc::MessageChannel::RunMessage(mozilla::ipc::MessageChannel::MessageTask&) /ipc/glue/MessageChannel.cpp:1826:3
        #45 0x7feee5735e3b in mozilla::ipc::MessageChannel::MessageTask::Run() /ipc/glue/MessageChannel.cpp:1857:13
        #46 0x7feee4cf983e in mozilla::RunnableTask::Run() /xpcom/threads/TaskController.cpp:502:16
        #47 0x7feee4cd4b0f in mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /xpcom/threads/TaskController.cpp:805:26
        #48 0x7feee4cd3778 in mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /xpcom/threads/TaskController.cpp:641:15
        #49 0x7feee4cd39f3 in mozilla::TaskController::ProcessPendingMTTask(bool) /xpcom/threads/TaskController.cpp:425:36
        #50 0x7feee4cfcea9 in operator() /xpcom/threads/TaskController.cpp:138:37
        #51 0x7feee4cfcea9 in mozilla::detail::RunnableFunction<mozilla::TaskController::InitializeInternal()::$_1>::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:531:5
        #52 0x7feee4ce82ef in nsThread::ProcessNextEvent(bool, bool*) /xpcom/threads/nsThread.cpp:1148:16
        #53 0x7feee4cef03a in NS_ProcessNextEvent(nsIThread*, bool) /xpcom/threads/nsThreadUtils.cpp:466:10
        #54 0x7feee573d124 in mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) /ipc/glue/MessagePump.cpp:107:5
        #55 0x7feee565d867 in MessageLoop::RunInternal() /ipc/chromium/src/base/message_loop.cc:331:10
        #56 0x7feee565d772 in RunHandler /ipc/chromium/src/base/message_loop.cc:324:3
        #57 0x7feee565d772 in MessageLoop::Run() /ipc/chromium/src/base/message_loop.cc:306:3
        #58 0x7feee95ec6c8 in nsBaseAppShell::Run() /widget/nsBaseAppShell.cpp:137:27
        #59 0x7feeeb46cf33 in XRE_RunAppShell() /toolkit/xre/nsEmbedFunctions.cpp:917:20
        #60 0x7feee573e06a in mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) /ipc/glue/MessagePump.cpp:235:9
        #61 0x7feee565d867 in MessageLoop::RunInternal() /ipc/chromium/src/base/message_loop.cc:331:10
        #62 0x7feee565d772 in RunHandler /ipc/chromium/src/base/message_loop.cc:324:3
        #63 0x7feee565d772 in MessageLoop::Run() /ipc/chromium/src/base/message_loop.cc:306:3
        #64 0x7feeeb46c56e in XRE_InitChildProcess(int, char**, XREChildData const*) /toolkit/xre/nsEmbedFunctions.cpp:749:34
        #65 0x55c80051dab6 in content_process_main /browser/app/../../ipc/contentproc/plugin-container.cpp:57:28
        #66 0x55c80051dab6 in main /browser/app/nsBrowserApp.cpp:327:18
        #67 0x7feefa4b30b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
        #68 0x55c8004fa8bc in _start (/home/jkratzer/builds/mc-debug/firefox-bin+0x158bc)
    
    UndefinedBehaviorSanitizer can not provide additional info.
    SUMMARY: UndefinedBehaviorSanitizer: SEGV /builds/worker/workspace/obj-build/dist/include/nsDisplayList.h:275:5 in PickDescendant
    ==784958==ABORTING
```
Testcase found while fuzzing mozilla-central rev f4ad9b76e5f8 (built with: --enable-debug --enable-fuzzing).

Testcase can be reproduced using the following commands:
$ pip install fuzzfetch grizzly-framework
$ python -m fuzzfetch --build f4ad9b76e5f8 --debug --fuzzing -n firefox
$ python -m grizzly.replay ./firefox/firefox testcase.zip
Testcase found while fuzzing mozilla-central rev f4ad9b76e5f8 (built with: --enable-debug --enable-fuzzing).

Testcase can be reproduced using the following commands:
```
$ pip install fuzzfetch grizzly-framework
$ python -m fuzzfetch --build f4ad9b76e5f8 --debug --fuzzing -n firefox
$ python -m grizzly.replay ./firefox/firefox testcase.zip
```
Testcase found while fuzzing mozilla-central rev f4ad9b76e5f8 (built with: --enable-debug --enable-fuzzing).

Testcase can be reproduced using the following commands:

$ pip install fuzzfetch grizzly-framework
$ python -m fuzzfetch --build f4ad9b76e5f8 --debug --fuzzing -n firefox
$ python -m grizzly.replay ./firefox/firefox testcase.zip

Back to Bug 1427792 Comment 16