1726637 - Crash in [@ InvalidArrayIndex_CRASH | nsHtml5Highlighter::Push]

Status: RESOLVED WORKSFORME

(Core :: DOM: HTML Parser, defect)

Description

[Andrew McCreight [:mccr8]]

Crash report: https://crash-stats.mozilla.org/report/index/17cdaf7f-67de-4485-863c-30ab60210819

MOZ_CRASH Reason: ElementAt(aIndex = 18446744073709551615, aLength = 0)

Top 10 frames of crashing thread:

0 libxul.so InvalidArrayIndex_CRASH xpcom/ds/nsTArray.cpp:28
1 libxul.so nsHtml5Highlighter::Push parser/html/nsHtml5Highlighter.cpp:652
2 libxul.so nsHtml5Highlighter::StartCharacters parser/html/nsHtml5Highlighter.cpp:509
3 libxul.so nsHtml5Highlighter::Transition parser/html/nsHtml5Highlighter.cpp:418
4 libxul.so int nsHtml5Tokenizer::stateLoop<nsHtml5ViewSourcePolicy> parser/html/nsHtml5Tokenizer.cpp:3576
5 libxul.so nsHtml5Tokenizer::tokenizeBuffer parser/html/nsHtml5Tokenizer.cpp:438
6 libxul.so nsHtml5StreamParser::ParseAvailableData parser/html/nsHtml5StreamParser.cpp:1906
7 libxul.so nsHtml5StreamParser::DoDataAvailable parser/html/nsHtml5StreamParser.cpp:1604
8 libxul.so nsHtml5StreamParser::DoDataAvailableBuffer parser/html/nsHtml5StreamParser.cpp:1520
9 libxul.so nsHtml5DataAvailable::Run parser/html/nsHtml5StreamParser.cpp:1634

18446744073709551615 is -1. My guess is that this is happening in nsHtml5Highlighter::Push() inside CurrentNode(), which does mStack[mStack.Length() - 1];, which will end up trying to get the -1'th element if mStack is empty. I only see two crashes from a single installation so maybe it isn't a big deal.

Comment 1

[Andrew McCreight [:mccr8]]

Looks like it is actually 3 crashes from 2 installations.

Comment 2

[Henri Sivonen (:hsivonen) (away from Bugzilla until 2025-10-27)]

For now, let's guess that this is bug 1726374 and let's see if this goes away once that lands.

Comment 3

[Henri Sivonen (:hsivonen) (away from Bugzilla until 2025-10-27)]

Looking at the stack, bug 1541822 is another possible cause.

Comment 4

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

Closing because no crashes reported for 12 weeks.