From: Eli Zaretskii <eliz@gnu.org>
To: "Óscar Fuentes" <ofv@wanadoo.es>
Cc: emacs-devel@gnu.org
Subject: Re: warnings compiling emacs28 with gcc 12.1
Date: Thu, 28 Jul 2022 20:38:23 +0300 [thread overview]
Message-ID: <83lesd87e8.fsf@gnu.org> (raw)
In-Reply-To: <87bkt9rwkf.fsf@telefonica.net> (message from Óscar Fuentes on Thu, 28 Jul 2022 19:12:00 +0200)
> From: Óscar Fuentes <ofv@wanadoo.es>
> Date: Thu, 28 Jul 2022 19:12:00 +0200
>
> Eli Zaretskii <eliz@gnu.org> writes:
>
> >> and there's another one about free that looks a bit scary:
> >>
> >> alloc.c: In function ‘lisp_free’:
> >> alloc.c:1052:3: warning: pointer ‘block’ used after ‘free’ [-Wuse-after-free]
> >> 1052 | mem_delete (mem_find (block));
> >> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> alloc.c:1050:3: note: call to ‘free’ here
> >> 1050 | free (block);
> >> | ^~~~~~~~~~~~
> >
> > Another nonsense. Look in mem_find, and you will see that it uses its
> > argument as just a number, it never dereferences it.
>
> The warning is not about dereferencing the pointer.
What other problems could be caused by using it after freeing it?
next prev parent reply other threads:[~2022-07-28 17:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-28 3:32 warnings compiling emacs28 with gcc 12.1 Jose A. Ortega Ruiz
2022-07-28 17:02 ` Eli Zaretskii
2022-07-28 17:12 ` Óscar Fuentes
2022-07-28 17:38 ` Eli Zaretskii [this message]
2022-07-28 18:31 ` Andreas Schwab
2022-07-28 18:35 ` Óscar Fuentes
2022-07-28 17:23 ` Jose A. Ortega Ruiz
2022-07-28 18:13 ` Lars Ingebrigtsen
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