Found while fuzzing m-c 20240201-366005a91eda (--enable-debug --enable-fuzzing)

To reproduce via Grizzly Replay:

$ pip install fuzzfetch grizzly-framework
$ python -m fuzzfetch -d --fuzzing -n firefox
$ python -m grizzly.replay.bugzilla ./firefox/firefox <bugid>

Assertion failure: !nif || (!mFloats.ContainsFrame(nif) && !mFrames.ContainsFrame(nif)), at /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:8546

#0 0x7f89136d66a8 in nsBlockFrame::VerifyOverflowSituation() /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:8545:7
#1 0x7f89136ce165 in nsBlockFrame::DrainOverflowLines() /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:5632:3
#2 0x7f89136ccab2 in nsBlockFrame::TrialReflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsBlockFrame::TrialReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:1858:3
#3 0x7f89136cb00b in nsBlockFrame::Reflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:1556:9
#4 0x7f89136dbe99 in nsBlockReflowContext::ReflowBlock(mozilla::LogicalRect const&, bool, nsCollapsingMargin&, int, nsLineBox*, mozilla::ReflowInput&, nsReflowStatus&, mozilla::BlockReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockReflowContext.cpp:290:11
#5 0x7f89136e5b01 in nsBlockFrame::ReflowFloat(mozilla::BlockReflowState&, mozilla::ReflowInput&, nsIFrame*, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:7094:9
#6 0x7f891369262d in mozilla::BlockReflowState::FlowAndPlaceFloat(nsIFrame*, mozilla::Maybe<int>) /builds/worker/checkouts/gecko/layout/generic/BlockReflowState.cpp:849:13
#7 0x7f89136947aa in mozilla::BlockReflowState::PlaceBelowCurrentLineFloats(nsLineBox*) /builds/worker/checkouts/gecko/layout/generic/BlockReflowState.cpp:1021:31
#8 0x7f89136df0b7 in nsBlockFrame::PlaceLine(mozilla::BlockReflowState&, nsLineLayout&, nsLineList_iterator, nsFloatManager::SavedState*, nsFlowAreaRect&, int&, bool*) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:5516:12
#9 0x7f89136dd7d6 in nsBlockFrame::DoReflowInlineFrames(mozilla::BlockReflowState&, nsLineLayout&, nsLineList_iterator, nsFlowAreaRect&, int&, nsFloatManager::SavedState*, bool*, LineReflowStatus*, bool) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:4943:12
#10 0x7f89136d9078 in nsBlockFrame::ReflowInlineFrames(mozilla::BlockReflowState&, nsLineList_iterator, bool*) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:4688:9
#11 0x7f89136d5488 in nsBlockFrame::ReflowLine(mozilla::BlockReflowState&, nsLineList_iterator, bool*) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:3656:24
#12 0x7f89136d00c1 in nsBlockFrame::ReflowDirtyLines(mozilla::BlockReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:3162:29
#13 0x7f89136cce0b in nsBlockFrame::TrialReflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsBlockFrame::TrialReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:1911:35
#14 0x7f89136cb00b in nsBlockFrame::Reflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:1556:9
#15 0x7f89136dbe99 in nsBlockReflowContext::ReflowBlock(mozilla::LogicalRect const&, bool, nsCollapsingMargin&, int, nsLineBox*, mozilla::ReflowInput&, nsReflowStatus&, mozilla::BlockReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockReflowContext.cpp:290:11
#16 0x7f89136e5b01 in nsBlockFrame::ReflowFloat(mozilla::BlockReflowState&, mozilla::ReflowInput&, nsIFrame*, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:7094:9
#17 0x7f891369262d in mozilla::BlockReflowState::FlowAndPlaceFloat(nsIFrame*, mozilla::Maybe<int>) /builds/worker/checkouts/gecko/layout/generic/BlockReflowState.cpp:849:13
#18 0x7f89136916e2 in mozilla::BlockReflowState::AddFloat(nsLineLayout*, nsIFrame*, int) /builds/worker/checkouts/gecko/layout/generic/BlockReflowState.cpp:580:9
#19 0x7f89137f64ee in nsLineLayout::ReflowFrame(nsIFrame*, nsReflowStatus&, mozilla::ReflowOutput*, bool&) /builds/worker/checkouts/gecko/layout/generic/nsLineLayout.cpp:936:23
#20 0x7f89136ddf7f in nsBlockFrame::ReflowInlineFrame(mozilla::BlockReflowState&, nsLineLayout&, nsLineList_iterator, nsIFrame*, LineReflowStatus*) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:5014:15
#21 0x7f89136dd179 in nsBlockFrame::DoReflowInlineFrames(mozilla::BlockReflowState&, nsLineLayout&, nsLineList_iterator, nsFlowAreaRect&, int&, nsFloatManager::SavedState*, bool*, LineReflowStatus*, bool) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:4816:5
#22 0x7f89136d9078 in nsBlockFrame::ReflowInlineFrames(mozilla::BlockReflowState&, nsLineList_iterator, bool*) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:4688:9
#23 0x7f89136d5488 in nsBlockFrame::ReflowLine(mozilla::BlockReflowState&, nsLineList_iterator, bool*) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:3656:24
#24 0x7f89136d00c1 in nsBlockFrame::ReflowDirtyLines(mozilla::BlockReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:3162:29
#25 0x7f89136cce0b in nsBlockFrame::TrialReflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsBlockFrame::TrialReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:1911:35
#26 0x7f89136cb00b in nsBlockFrame::Reflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:1556:9
#27 0x7f8913700644 in nsContainerFrame::ReflowChild(nsIFrame*, nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, mozilla::WritingMode const&, mozilla::LogicalPoint const&, nsSize const&, nsIFrame::ReflowChildFlags, nsReflowStatus&, nsOverflowContinuationTracker*) /builds/worker/checkouts/gecko/layout/generic/nsContainerFrame.cpp:886:14
#28 0x7f89136f0c65 in nsColumnSetFrame::ReflowColumns(mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&, nsColumnSetFrame::ReflowConfig const&, bool) /builds/worker/checkouts/gecko/layout/generic/nsColumnSetFrame.cpp:700:7
#29 0x7f89136f2d07 in nsColumnSetFrame::Reflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsColumnSetFrame.cpp:1245:37
#30 0x7f89136dbe99 in nsBlockReflowContext::ReflowBlock(mozilla::LogicalRect const&, bool, nsCollapsingMargin&, int, nsLineBox*, mozilla::ReflowInput&, nsReflowStatus&, mozilla::BlockReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockReflowContext.cpp:290:11
#31 0x7f89136d7cd0 in nsBlockFrame::ReflowBlockFrame(mozilla::BlockReflowState&, nsLineList_iterator, bool*) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:4323:11
#32 0x7f89136d553d in nsBlockFrame::ReflowLine(mozilla::BlockReflowState&, nsLineList_iterator, bool*) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:3653:5
#33 0x7f89136d00c1 in nsBlockFrame::ReflowDirtyLines(mozilla::BlockReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:3162:29
#34 0x7f89136cce0b in nsBlockFrame::TrialReflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsBlockFrame::TrialReflowState&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:1911:35
#35 0x7f89136cb00b in nsBlockFrame::Reflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsBlockFrame.cpp:1556:9
#36 0x7f8913700644 in nsContainerFrame::ReflowChild(nsIFrame*, nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, mozilla::WritingMode const&, mozilla::LogicalPoint const&, nsSize const&, nsIFrame::ReflowChildFlags, nsReflowStatus&, nsOverflowContinuationTracker*) /builds/worker/checkouts/gecko/layout/generic/nsContainerFrame.cpp:886:14
#37 0x7f89136ee5cb in nsCanvasFrame::Reflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsCanvasFrame.cpp:757:7
#38 0x7f8913700644 in nsContainerFrame::ReflowChild(nsIFrame*, nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, mozilla::WritingMode const&, mozilla::LogicalPoint const&, nsSize const&, nsIFrame::ReflowChildFlags, nsReflowStatus&, nsOverflowContinuationTracker*) /builds/worker/checkouts/gecko/layout/generic/nsContainerFrame.cpp:886:14
#39 0x7f8913746397 in nsHTMLScrollFrame::ReflowScrolledFrame(mozilla::ScrollReflowInput&, bool, bool, mozilla::ReflowOutput*) /builds/worker/checkouts/gecko/layout/generic/nsGfxScrollFrame.cpp:940:3
#40 0x7f891374726e in nsHTMLScrollFrame::ReflowContents(mozilla::ScrollReflowInput&, mozilla::ReflowOutput const&) /builds/worker/checkouts/gecko/layout/generic/nsGfxScrollFrame.cpp:1073:3
#41 0x7f891374be7c in nsHTMLScrollFrame::Reflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/nsGfxScrollFrame.cpp:1507:3
#42 0x7f8913700b31 in nsContainerFrame::ReflowChild(nsIFrame*, nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, int, int, nsIFrame::ReflowChildFlags, nsReflowStatus&, nsOverflowContinuationTracker*) /builds/worker/checkouts/gecko/layout/generic/nsContainerFrame.cpp:927:14
#43 0x7f89136c0ef2 in mozilla::ViewportFrame::Reflow(nsPresContext*, mozilla::ReflowOutput&, mozilla::ReflowInput const&, nsReflowStatus&) /builds/worker/checkouts/gecko/layout/generic/ViewportFrame.cpp:368:7
#44 0x7f89135aa764 in mozilla::PresShell::DoReflow(nsIFrame*, bool, mozilla::OverflowChangedTracker*) /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:9765:11
#45 0x7f89135d3f0f in mozilla::PresShell::ProcessReflowCommands(bool) /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:9938:22
#46 0x7f89135b4c23 in DoFlushLayout /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:9985:10
#47 0x7f89135b4c23 in mozilla::PresShell::DoFlushPendingNotifications(mozilla::ChangesToFlush) /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:4349:11
#48 0x7f89113cd88d in FlushPendingNotifications /builds/worker/workspace/obj-build/dist/include/mozilla/PresShell.h:1465:5
#49 0x7f89113cd88d in mozilla::EventStateManager::FlushLayout(nsPresContext*) /builds/worker/checkouts/gecko/dom/events/EventStateManager.cpp:6190:16
#50 0x7f89113c9ba4 in mozilla::EventStateManager::PreHandleEvent(nsPresContext*, mozilla::WidgetEvent*, nsIFrame*, nsIContent*, nsEventStatus*, nsIContent*) /builds/worker/checkouts/gecko/dom/events/EventStateManager.cpp:853:7
#51 0x7f89135cc51d in mozilla::PresShell::EventHandler::DispatchEvent(mozilla::EventStateManager*, mozilla::WidgetEvent*, bool, nsEventStatus*, nsIContent*) /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:8363:39
#52 0x7f89135c6096 in mozilla::PresShell::EventHandler::HandleEventWithCurrentEventInfo(mozilla::WidgetEvent*, nsEventStatus*, bool, nsIContent*) /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:8332:17
#53 0x7f89135c5852 in mozilla::PresShell::EventHandler::HandleEventUsingCoordinates(nsIFrame*, mozilla::WidgetGUIEvent*, nsEventStatus*, bool) /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:7247:30
#54 0x7f89135c41f8 in mozilla::PresShell::EventHandler::HandleEvent(nsIFrame*, mozilla::WidgetGUIEvent*, bool, nsEventStatus*) /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:7045:12
#55 0x7f89135c3661 in mozilla::PresShell::HandleEvent(nsIFrame*, mozilla::WidgetGUIEvent*, bool, nsEventStatus*) /builds/worker/checkouts/gecko/layout/base/PresShell.cpp:6988:23
#56 0x7f891314434e in nsViewManager::DispatchEvent(mozilla::WidgetGUIEvent*, nsView*, nsEventStatus*) /builds/worker/checkouts/gecko/view/nsViewManager.cpp:653:18
#57 0x7f89131440a9 in nsView::HandleEvent(mozilla::WidgetGUIEvent*, bool) /builds/worker/checkouts/gecko/view/nsView.cpp:1136:9
#58 0x7f891317f891 in mozilla::widget::PuppetWidget::DispatchEvent(mozilla::WidgetGUIEvent*, nsEventStatus&) /builds/worker/checkouts/gecko/widget/PuppetWidget.cpp:348:37
#59 0x7f890f0fb90b in mozilla::layers::APZCCallbackHelper::DispatchWidgetEvent(mozilla::WidgetGUIEvent&) /builds/worker/checkouts/gecko/gfx/layers/apz/util/APZCCallbackHelper.cpp:506:21
#60 0x7f89128b3294 in DispatchWidgetEventViaAPZ /builds/worker/checkouts/gecko/dom/ipc/BrowserChild.cpp:1677:10
#61 0x7f89128b3294 in mozilla::dom::BrowserChild::HandleRealMouseButtonEvent(mozilla::WidgetMouseEvent const&, mozilla::layers::ScrollableLayerGuid const&, unsigned long const&) /builds/worker/checkouts/gecko/dom/ipc/BrowserChild.cpp:1640:3
#62 0x7f89128b49ab in mozilla::dom::BrowserChild::RecvRealMouseButtonEvent(mozilla::WidgetMouseEvent const&, mozilla::layers::ScrollableLayerGuid const&, unsigned long const&) /builds/worker/checkouts/gecko/dom/ipc/BrowserChild.cpp:1607:3
#63 0x7f89128b4b18 in mozilla::dom::BrowserChild::RecvSynthMouseMoveEvent(mozilla::WidgetMouseEvent const&, mozilla::layers::ScrollableLayerGuid const&, unsigned long const&) /builds/worker/checkouts/gecko/dom/ipc/BrowserChild.cpp:1572:8
#64 0x7f89129e8ec3 in mozilla::dom::PBrowserChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PBrowserChild.cpp:5489:80
#65 0x7f8912a73a80 in mozilla::dom::PContentChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PContentChild.cpp:8261:32
#66 0x7f890e9577cf in mozilla::ipc::MessageChannel::DispatchAsyncMessage(mozilla::ipc::ActorLifecycleProxy*, IPC::Message const&) /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1813:25
#67 0x7f890e954522 in mozilla::ipc::MessageChannel::DispatchMessage(mozilla::ipc::ActorLifecycleProxy*, mozilla::UniquePtr<IPC::Message, mozilla::DefaultDelete<IPC::Message>>) /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1732:9
#68 0x7f890e9551a2 in mozilla::ipc::MessageChannel::RunMessage(mozilla::ipc::ActorLifecycleProxy*, mozilla::ipc::MessageChannel::MessageTask&) /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1525:3
#69 0x7f890e9562ef in mozilla::ipc::MessageChannel::MessageTask::Run() /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1623:14
#70 0x7f890dc65a77 in mozilla::RunnableTask::Run() /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:578:16
#71 0x7f890dc5b1e6 in mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:905:26
#72 0x7f890dc599c7 in mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:728:15
#73 0x7f890dc59e45 in mozilla::TaskController::ProcessPendingMTTask(bool) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:514:36
#74 0x7f890dc69a16 in operator() /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:232:37
#75 0x7f890dc69a16 in mozilla::detail::RunnableFunction<mozilla::TaskController::TaskController()::$_0>::Run() /builds/worker/checkouts/gecko/xpcom/threads/nsThreadUtils.h:548:5
#76 0x7f890dc7ed82 in nsThread::ProcessNextEvent(bool, bool*) /builds/worker/checkouts/gecko/xpcom/threads/nsThread.cpp:1199:16
#77 0x7f890dc85ecd in NS_ProcessNextEvent(nsIThread*, bool) /builds/worker/checkouts/gecko/xpcom/threads/nsThreadUtils.cpp:480:10
#78 0x7f890e95d735 in mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) /builds/worker/checkouts/gecko/ipc/glue/MessagePump.cpp:85:21
#79 0x7f890e8779d1 in RunHandler /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:363:3
#80 0x7f890e8779d1 in MessageLoop::Run() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:345:3
#81 0x7f89131afda8 in nsBaseAppShell::Run() /builds/worker/checkouts/gecko/widget/nsBaseAppShell.cpp:148:27
#82 0x7f891326d3e8 in nsAppShell::Run() /builds/worker/checkouts/gecko/widget/gtk/nsAppShell.cpp:470:33
#83 0x7f891508009b in XRE_RunAppShell() /builds/worker/checkouts/gecko/toolkit/xre/nsEmbedFunctions.cpp:721:20
#84 0x7f890e95e616 in mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) /builds/worker/checkouts/gecko/ipc/glue/MessagePump.cpp:235:9
#85 0x7f890e8779d1 in RunHandler /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:363:3
#86 0x7f890e8779d1 in MessageLoop::Run() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:345:3
#87 0x7f891507f902 in XRE_InitChildProcess(int, char**, XREChildData const*) /builds/worker/checkouts/gecko/toolkit/xre/nsEmbedFunctions.cpp:656:34
#88 0x562bbe9d43b6 in content_process_main /builds/worker/checkouts/gecko/browser/app/../../ipc/contentproc/plugin-container.cpp:57:28
#89 0x562bbe9d43b6 in main /builds/worker/checkouts/gecko/browser/app/nsBrowserApp.cpp:375:18
#90 0x7f8922429d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#91 0x7f8922429e3f in __libc_start_main csu/../csu/libc-start.c:392:3
#92 0x562bbe9aa0e8 in _start (/home/user/workspace/browsers/m-c-20240201173838-fuzzing-debug/firefox-bin+0x590e8) (BuildId: 3158970e7ac1bc3dd3d8206f2d8c2427846e3ccf)

Verified bug as reproducible on mozilla-central 20240202164508-90d84a362f05.
The bug appears to have been introduced in the following build range:

Start: 08207806be4c7c13165c07ab2cf6dd811da2e198 (20230517033250)
End: f76409005dd49f1a1197f80fc7fadd31c7a8638b (20230516214329)
Pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=08207806be4c7c13165c07ab2cf6dd811da2e198&tochange=f76409005dd49f1a1197f80fc7fadd31c7a8638b

: TYLin could this be caused by bug 1833238?

(In reply to Dianna Smith [:diannaS] from comment #2)

: TYLin could this be caused by bug 1833238?

It is possible. However, I failed to reproduce the assertion with the steps in comment 0. I tried the following command.

$ python3 -m fuzzfetch -d --fuzzing -n firefox # This download firefox with build id 20240205205906.
$ python3 -m grizzly.replay.bugzilla ./firefox/firefox 1878424

The log is

[2024-02-05 14:07:44] Loaded Bug 1878424 from Bugzilla
[2024-02-05 14:07:44] Starting Grizzly Replay
[2024-02-05 14:07:44] Ignoring: log-limit, timeout
[2024-02-05 14:07:44] Using time limit: 30s, timeout: 45s
[2024-02-05 14:07:44] Repeat: 1, Minimum crashes: 1, Relaunch 1
[2024-02-05 14:07:44] HTTPS support requires NSS certutil.
[2024-02-05 14:07:44] Target does not support HTTPS, using HTTP
[2024-02-05 14:07:49] Running test (1/1)...
[2024-02-05 14:08:22] No results detected
[2024-02-05 14:08:22] Shutting down...
[2024-02-05 14:08:22] Done.

I also see no assertion loading the testcase directly in my local debug build on latest m-c.

Tyson, could you check if the fuzzer got another testcase?

oh hmm seems to require the --xvfb arg when calling grizzly.replay (depends on window dimensions?). Sorry I missed that.

Let me know if that works for you.

Ah, python3 -m grizzly.replay.bugzilla --xvfb ./firefox/firefox 1878424 reproduces the assertion. Thanks!

Although loading the testcase directly in debug doesn't reproduce the assertion, but I see several soft assertions like:

###!!! ASSERTION: nsBlockFrame::CheckFloats: Explicit float list is out of sync with float cache

This should be a good first step for investigation.

Since this was reproducible by bugmon you can add the pernosco keyword if you'd like a Pernosco session.