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From: Eli Zaretskii <eliz@gnu.org>
Newsgroups: gmane.emacs.devel
Subject: Re: Null pointer dereference?
Date: Fri, 12 May 2017 22:17:15 +0300
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To: Zubin Mevawalla <zubinmeva@qbitlogic.com>
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> From: Zubin Mevawalla <zubinmeva@qbitlogic.com>
> Date: Fri, 12 May 2017 11:45:53 -0400
> 
> I was curious if this was a real null pointer dereference issue, in
> etags.c on line 2265?

I don't think so.

> `np_parent` is initialized to NULL on 2248. if `np` is not NULL and
> `np->fdp == badfdp` then `np_parent->left` on line 2265 would result
> in a null pointer dereference.

np->fdp == badfdp cannot happen the first time the loop condition is
tested, because np was initialized to point to super_root, and
super_root.fdp was initialized to -1, which can never be equal to
badfdp.

Thanks.