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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - NULL Reference Error in ElementRuleCollector"
href="https://bugs.webkit.org/show_bug.cgi?id=160362#c6">Comment # 6</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - NULL Reference Error in ElementRuleCollector"
href="https://bugs.webkit.org/show_bug.cgi?id=160362">bug 160362</a>
from <span class="vcard"><a class="email" href="mailto:jbedard@apple.com" title="Jonathan Bedard <jbedard@apple.com>"> <span class="fn">Jonathan Bedard</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=160362#c5">comment #5</a>)
<span class="quote">> > undefined behavior, although surprisingly, many of the tests which exhibit
> > this (canvas/philip/tests/2d.strokeRect.path.html, for example) still pass.
>
> Null pointer dereference always crashes. How do the tests "exhibit" this?</span >
This bug was found through open source clang's undefined behavior sanitizer. As far as I can tell, a reference is being bound to a dereferenced NULL pointer but then this reference is never used. If the reference were used, we would see a crash.
Tests "exhibit" this (not even sure if that's the right way to describe this) when the undefined behavior sanitizer flags the reference being bound to a dereferenced NULL pointer during runtime.</pre>
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