From: Ingo Oeser <ioe-lkml@rameria.de>
To: Bernd Petrovitsch <bernd@firmix.at>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>,
Pavel Machek <pavel@ucw.cz>, Amit Choudhary <amit2030@yahoo.com>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] [DISCUSS] Make the variable NULL after freeing it.
Date: Mon, 1 Jan 2007 01:43:00 +0100 [thread overview]
Message-ID: <200701010143.02870.ioe-lkml@rameria.de> (raw)
In-Reply-To: <1167572312.3318.47.camel@gimli.at.home>
On Sunday, 31. December 2006 14:38, Bernd Petrovitsch wrote:
> That depends on the decision/definition if (so called) "double free" is
> an error or not (and "free(NULL)" must work in POSIX-compliant
> environments).
A double free of non-NULL is certainly an error.
So the idea of setting it to NULL is ok, since then you can
kfree the variable over and over again without any harm.
It is just complicated to do this side effect free.
Maybe one should check for builtin-constant and take the address,
if this is not an builtin-constant.
sth, like this
#define kfree_nullify(x) do { \
if (__builtin_constant_p(x)) { \
kfree(x); \
} else { \
typeof(x) *__addr_x = &x; \
kfree(*__addr_x); \
*__addr_x = NULL; \
} \
} while (0)
Regards
Ingo Oeser
next prev parent reply other threads:[~2007-01-01 0:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-21 23:41 Amit Choudhary
2006-12-27 17:10 ` Pavel Machek
2006-12-28 8:54 ` Jan Engelhardt
2006-12-31 13:38 ` Bernd Petrovitsch
2007-01-01 0:43 ` Ingo Oeser [this message]
2007-01-01 1:05 ` YOSHIFUJI Hideaki / 吉藤英明
2007-01-01 6:37 ` Amit Choudhary
2007-01-01 16:09 ` Ingo Oeser
2007-01-01 16:25 ` Andreas Schwab
2007-01-01 21:40 ` Ingo Oeser
2007-01-01 21:42 ` Jan Engelhardt
2007-01-01 18:36 ` Pavel Machek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200701010143.02870.ioe-lkml@rameria.de \
--to=ioe-lkml@rameria.de \
--cc=amit2030@yahoo.com \
--cc=bernd@firmix.at \
--cc=jengelh@linux01.gwdg.de \
--cc=linux-kernel@vger.kernel.org \
--cc=pavel@ucw.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®