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From: Gerd Hoffmann <kraxel@redhat.com>
To: Paul Brook <paul@codesourcery.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
	qemu-devel@nongnu.org,
	Jean-Christophe Dubois <jcd@tribudubois.net>
Subject: Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently
Date: Fri, 29 May 2009 15:46:06 +0200	[thread overview]
Message-ID: <4A1FE71E.6040504@redhat.com> (raw)
In-Reply-To: <200905291407.26757.paul@codesourcery.com>

On 05/29/09 15:07, Paul Brook wrote:
> The best way to find broken code is to have qemu_malloc(0) abort, and avoid
> ever trying to allocate a zero size block.

Forces all call sizes where size=0 is a perfectly legal case add extra 
code to prevent qemu from aborting, i.e. replace

   ptr = qemu_malloc(len);

with

   if (len) {
     ptr = qemu_malloc(len);
   } else {
     ptr = NULL; /* make sure we don't pass garbage to qemu_free() */
   }

> If you want maximize chances of catching accidental mistakes as early as
> possible then you should have malloc(0) abort, because it probably means
> someone forgot tho consider the empty case.

I don't share the assumption that malloc(0) is a bug in most cases.  And 
on the other hand the slightly different behavior might actually 
introduce bugs because people assume qemu_malloc() works like malloc().

cheers,
   Gerd

  reply	other threads:[~2009-05-29 13:48 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-29  5:58 [Qemu-devel] [PATCH] use qemu_malloc and friends consistently Jean-Christophe Dubois
2009-05-29  8:42 ` Kevin Wolf
2009-05-29  9:05   ` Anthony Liguori
2009-05-29  9:51     ` malc
2009-05-29 10:05       ` Kevin Wolf
2009-05-29 10:23         ` malc
2009-05-29 10:34           ` Kevin Wolf
2009-05-29 10:40             ` malc
2009-05-29 10:49               ` Kevin Wolf
2009-05-29 10:56                 ` Anthony Liguori
2009-05-29 11:06                 ` malc
2009-05-29 11:14                   ` Kevin Wolf
2009-05-29 10:53       ` Anthony Liguori
2009-05-29 11:24         ` malc
2009-05-29 12:36           ` Gerd Hoffmann
2009-05-29 13:07             ` Paul Brook
2009-05-29 13:46               ` Gerd Hoffmann [this message]
2009-05-29 13:59               ` Glauber Costa
2009-05-29 14:34               ` Anthony Liguori
2009-05-29 15:06                 ` malc
2009-05-29 17:17               ` Julian Seward
2009-05-29 18:41                 ` Gerd Hoffmann
2009-05-29 21:12                 ` David Turner
2009-05-29 21:13                   ` David Turner
2009-06-02  7:26                   ` Gerd Hoffmann
2009-06-02  7:47                     ` Anthony Liguori
2009-06-02  8:58                       ` Daniel P. Berrange
2009-06-02 18:03                         ` David Turner
2009-06-02  8:48                     ` Avi Kivity
2009-06-02 18:02                     ` David Turner
2009-06-02 18:13                       ` Paul Brook
2009-06-02 19:49                         ` David Turner
2009-06-02 20:04                           ` Paul Brook
2009-06-02 20:42                             ` David Turner
2009-06-02 20:45                               ` Gerd Hoffmann
2009-06-02 20:48                               ` Gerd Hoffmann
2009-06-02 20:58                               ` Paul Brook
2009-06-02 21:19                                 ` David Turner
2009-06-02 19:03                       ` Avi Kivity
2009-05-29 12:51           ` Markus Armbruster
2009-05-29 10:57       ` Gerd Hoffmann
2009-05-29 11:28         ` malc
2009-05-29  9:28   ` jcd
2009-05-29  9:38     ` Kevin Wolf
2009-06-01 11:59     ` Jamie Lokier
     [not found] <18212122.68761243590277678.JavaMail.root@srv-05.w4a.fr>
2009-05-29 10:00 ` jcd
2009-05-29 10:10   ` Kevin Wolf
     [not found] <2171027.69001243598252547.JavaMail.root@srv-05.w4a.fr>
2009-05-29 12:00 ` jcd
2009-05-29 12:05   ` Kevin Wolf
2009-05-29 12:13     ` jcd
2009-05-29 12:32   ` Markus Armbruster
2009-05-29 12:38     ` jcd
     [not found] <28932640.69341243603994530.JavaMail.root@srv-05.w4a.fr>
2009-05-29 13:35 ` jcd
     [not found] <28912134.69441243608238156.JavaMail.root@srv-05.w4a.fr>
2009-05-29 14:46 ` jcd
     [not found] <33383337.69831243610071896.JavaMail.root@srv-05.w4a.fr>
2009-05-29 15:15 ` jcd
     [not found] <1758936.71791243858884274.JavaMail.root@srv-05.w4a.fr>
2009-06-01 12:24 ` jcd
2009-06-01 23:46   ` Jamie Lokier

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