1806486 - Assertion failure: hyperAcc, at /builds/worker/checkouts/gecko/accessible/base/TextLeafRange.cpp:1345

Status: VERIFIED FIXED

(Core :: Disability Access APIs, defect)

Description

[Tyson Smith [:tsmith]]

Attachment: testcase.html

Found while fuzzing m-c 20221218-4d46db3ff28b (--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 ./firefox/firefox testcase.html

Assertion failure: hyperAcc, at /builds/worker/checkouts/gecko/accessible/base/TextLeafRange.cpp:1345

#0 0x7ff599387a28 in mozilla::a11y::TextLeafPoint::GetTextAttributesLocalAcc(bool) const /builds/worker/checkouts/gecko/accessible/base/TextLeafRange.cpp:1345:3
#1 0x7ff5993bb5ad in mozilla::a11y::LocalAccessible::BundleFieldsForCache(unsigned long, mozilla::a11y::CacheUpdateType) /builds/worker/checkouts/gecko/accessible/generic/LocalAccessible.cpp:3333:45
#2 0x7ff5993ef487 in mozilla::a11y::DocAccessibleChildBase::InsertIntoIpcTree(mozilla::a11y::LocalAccessible*, mozilla::a11y::LocalAccessible*, unsigned int, bool) /builds/worker/checkouts/gecko/accessible/ipc/DocAccessibleChildBase.cpp:106:16
#3 0x7ff5993bef47 in mozilla::a11y::DocAccessible::DoInitialUpdate() /builds/worker/checkouts/gecko/accessible/generic/DocAccessible.cpp:1698:17
#4 0x7ff5993730ba in mozilla::a11y::NotificationController::WillRefresh(mozilla::TimeStamp) /builds/worker/checkouts/gecko/accessible/base/NotificationController.cpp:671:16
#5 0x7ff597b82cb2 in nsRefreshDriver::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsRefreshDriver::IsExtraTick) /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:2550:12
#6 0x7ff597b8c9bd in TickDriver /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:374:13
#7 0x7ff597b8c9bd in mozilla::RefreshDriverTimer::TickRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsTArray<RefPtr<nsRefreshDriver>>&) /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:352:7
#8 0x7ff597b8c8c3 in mozilla::RefreshDriverTimer::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:368:5
#9 0x7ff597b8c7a0 in mozilla::VsyncRefreshDriverTimer::RunRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:912:5
#10 0x7ff597b8bb0a in mozilla::VsyncRefreshDriverTimer::TickRefreshDriver(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:826:5
#11 0x7ff597b8b2c6 in mozilla::VsyncRefreshDriverTimer::NotifyVsyncOnMainThread(mozilla::VsyncEvent const&) /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:747:5
#12 0x7ff597b8add9 in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyVsyncTimerOnMainThread() /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:593:14
#13 0x7ff597b8a9ed in mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyVsync(mozilla::VsyncEvent const&) /builds/worker/checkouts/gecko/layout/base/nsRefreshDriver.cpp:550:9
#14 0x7ff5970415db in mozilla::dom::VsyncMainChild::RecvNotify(mozilla::VsyncEvent const&, float const&) /builds/worker/checkouts/gecko/dom/ipc/VsyncMainChild.cpp:68:15
#15 0x7ff5972cb098 in mozilla::dom::PVsyncChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PVsyncChild.cpp:220:78
#16 0x7ff5971dd40b in mozilla::dom::PContentChild::OnMessageReceived(IPC::Message const&) /builds/worker/workspace/obj-build/ipc/ipdl/PContentChild.cpp:8758:32
#17 0x7ff5933e680a in mozilla::ipc::MessageChannel::DispatchAsyncMessage(mozilla::ipc::ActorLifecycleProxy*, IPC::Message const&) /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1756:25
#18 0x7ff5933e3467 in mozilla::ipc::MessageChannel::DispatchMessage(mozilla::ipc::ActorLifecycleProxy*, mozilla::UniquePtr<IPC::Message, mozilla::DefaultDelete<IPC::Message>>) /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1681:9
#19 0x7ff5933e3fb5 in mozilla::ipc::MessageChannel::RunMessage(mozilla::ipc::ActorLifecycleProxy*, mozilla::ipc::MessageChannel::MessageTask&) /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1481:3
#20 0x7ff5933e52ef in mozilla::ipc::MessageChannel::MessageTask::Run() /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1579:14
#21 0x7ff5927e1785 in mozilla::RunnableTask::Run() /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:539:16
#22 0x7ff5927dcd5c in mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:852:26
#23 0x7ff5927db92a in mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:684:15
#24 0x7ff5927dbc85 in mozilla::TaskController::ProcessPendingMTTask(bool) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:462:36
#25 0x7ff5927e5086 in operator() /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:188:37
#26 0x7ff5927e5086 in mozilla::detail::RunnableFunction<mozilla::TaskController::InitializeInternal()::$_2>::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:546:5
#27 0x7ff5927faa95 in nsThread::ProcessNextEvent(bool, bool*) /builds/worker/checkouts/gecko/xpcom/threads/nsThread.cpp:1209:16
#28 0x7ff5928012dd in NS_ProcessNextEvent(nsIThread*, bool) /builds/worker/checkouts/gecko/xpcom/threads/nsThreadUtils.cpp:476:10
#29 0x7ff5933ec0e3 in mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) /builds/worker/checkouts/gecko/ipc/glue/MessagePump.cpp:85:21
#30 0x7ff593310d78 in MessageLoop::RunInternal() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:381:10
#31 0x7ff593310c81 in RunHandler /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:374:3
#32 0x7ff593310c81 in MessageLoop::Run() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:356:3
#33 0x7ff597830008 in nsBaseAppShell::Run() /builds/worker/checkouts/gecko/widget/nsBaseAppShell.cpp:150:27
#34 0x7ff599a5ca4b in XRE_RunAppShell() /builds/worker/checkouts/gecko/toolkit/xre/nsEmbedFunctions.cpp:743:20
#35 0x7ff5933ecfa9 in mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) /builds/worker/checkouts/gecko/ipc/glue/MessagePump.cpp:235:9
#36 0x7ff593310d78 in MessageLoop::RunInternal() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:381:10
#37 0x7ff593310c81 in RunHandler /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:374:3
#38 0x7ff593310c81 in MessageLoop::Run() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:356:3
#39 0x7ff599a5c5a8 in XRE_InitChildProcess(int, char**, XREChildData const*) /builds/worker/checkouts/gecko/toolkit/xre/nsEmbedFunctions.cpp:676:34
#40 0x55edf3c37ca0 in content_process_main /builds/worker/checkouts/gecko/browser/app/../../ipc/contentproc/plugin-container.cpp:57:28
#41 0x55edf3c37ca0 in main /builds/worker/checkouts/gecko/browser/app/nsBrowserApp.cpp:359:18
#42 0x7ff5a5dafd8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#43 0x7ff5a5dafe3f in __libc_start_main csu/../csu/libc-start.c:392:3
#44 0x55edf3c0e308 in _start (/home/user/workspace/browsers/m-c-20221219162526-fuzzing-debug/firefox-bin+0x5b308) (BuildId: e066f9de05f28543bfbd459b238d810f08831b08)

Comment 1

[Tyson Smith [:tsmith]]

Attachment: prefs.js

prefs.js for bugmon

Comment 2

[Bugmon [:jkratzer for issues]]

Verified bug as reproducible on mozilla-central 20221219162526-91a9bbbe6bea.
The bug appears to have been introduced in the following build range:

Start: 2d625e5d6ff86fda6d83464bb315478f94afc577 (20221114233128)
End: 1adc82d1eb960a8a6aac68b9abceaac3fd491abb (20221115021943)
Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=2d625e5d6ff86fda6d83464bb315478f94afc577&tochange=1adc82d1eb960a8a6aac68b9abceaac3fd491abb

Comment 3

[James Teh [:Jamie]]

Attachment: Bug 1806486: If we're forced to create an Accessible for a MathML element which wouldn't normally have one, make it a HyperTextAccessible.

Certain MathML elements such as annotation and annotation-xml don't normally get an Accessible.
However, we force create Accessibles in some cases; e.g. if the element is focusable.
When this happens for these MathML elements (e.g. annotation-xml with a tabindex), we previously created AccessibleWraps which don't support text.
This meant that text formatting information was unavailable and caused assertions when pushing the cache.
To fix this, use HyperTextAccessibleWrap instead.

As a drive-by fix, also use HyperTextAccessibleWrap instead of HyperTextAccessible for content MathML elements.
This was almost certainly a typo when this was implemented.
This wouldn't have been noticeable in tests and some native platforms, but some platforms (e.g. Mac and Windows) do have some overrides in HyperTextAccessibleWrap, so we should use those.

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

Based on comment #2, this bug contains a bisection range found by bugmon. However, the Regressed by field is still not filled.

:Jamie, if possible, could you fill the Regressed by field and investigate this regression?

For more information, please visit auto_nag documentation.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9a4632210fa1
If we're forced to create an Accessible for a MathML element which wouldn't normally have one, make it a HyperTextAccessible. r=nlapre

Comment 6

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/9a4632210fa1

Comment 7

[Bugmon [:jkratzer for issues]]

Verified bug as fixed on rev mozilla-central 20221222094520-27a62fceb6f4.
Removing bugmon keyword as no further action possible. Please review the bug and re-add the keyword for further analysis.

Comment 8

[James Teh [:Jamie]]

If we had to pick a regressing bug, it would be when CTW was enabled.