From: Julia Lawall <julia.lawall@lip6.fr>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>,
Kalle Valo <kvalo@adurom.com>,
Julian Calaby <julian.calaby@gmail.com>,
"John W. Linville" <linville@tuxdriver.com>,
linux-wireless@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] wireless: at76c50x: allocating too much data
Date: Sat, 21 Apr 2012 17:13:06 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.02.1204211712270.1987@hadrien> (raw)
In-Reply-To: <20120421151235.GM27101@mwanda>
On Sat, 21 Apr 2012, Dan Carpenter wrote:
> On Sat, Apr 21, 2012 at 05:51:41PM +0300, Dan Carpenter wrote:
>> On Sat, Apr 21, 2012 at 03:51:44PM +0200, Julia Lawall wrote:
>>> Looking for x = ... sizeof(x) ... I get 9 reports. In most cases it
>>> looks like sizeof(x) is coincidentally the same as the size that is
>>> wanted. Two cases that look like they could have some noticible
>>> effect are:
>>>
>>> arch/xtensa/platforms/iss/network.c, line 789
>>> drivers/block/cciss.c, line 4211
>>>
>>
>> Clever. You'd need to restrict it to places where x was a pointer.
>> That's better than my check which was specific to kmalloc(). (So
>> uh... I'm going to rewrite mine as well to be more generic. :P)
>>
>
> Hm... Smatch is not really the right tool here. By the time Sparse
> gives you the sizeof(foo) information, it just looks like a number
> 8.
>
> I hacked up Sparse a bit so it works for simple expressions which
> are one token in from the c tokenizer. So:
>
> foo = kmalloc(sizeof(foo), GFP_KERNEL); => error.
> foo->bar = kmalloc(sizeof(foo->bar), GFP_KERNEL); => tricky.
>
> It's not ideal. Coccinelle is better for this.
On the other hand, Coccinelle has no idea what the size is, so it doesn't
know how important the problem is.
julia
WARNING: multiple messages have this Message-ID (diff)
From: Julia Lawall <julia.lawall@lip6.fr>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>,
Kalle Valo <kvalo@adurom.com>,
Julian Calaby <julian.calaby@gmail.com>,
"John W. Linville" <linville@tuxdriver.com>,
linux-wireless@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] wireless: at76c50x: allocating too much data
Date: Sat, 21 Apr 2012 15:13:06 +0000 [thread overview]
Message-ID: <alpine.DEB.2.02.1204211712270.1987@hadrien> (raw)
In-Reply-To: <20120421151235.GM27101@mwanda>
On Sat, 21 Apr 2012, Dan Carpenter wrote:
> On Sat, Apr 21, 2012 at 05:51:41PM +0300, Dan Carpenter wrote:
>> On Sat, Apr 21, 2012 at 03:51:44PM +0200, Julia Lawall wrote:
>>> Looking for x = ... sizeof(x) ... I get 9 reports. In most cases it
>>> looks like sizeof(x) is coincidentally the same as the size that is
>>> wanted. Two cases that look like they could have some noticible
>>> effect are:
>>>
>>> arch/xtensa/platforms/iss/network.c, line 789
>>> drivers/block/cciss.c, line 4211
>>>
>>
>> Clever. You'd need to restrict it to places where x was a pointer.
>> That's better than my check which was specific to kmalloc(). (So
>> uh... I'm going to rewrite mine as well to be more generic. :P)
>>
>
> Hm... Smatch is not really the right tool here. By the time Sparse
> gives you the sizeof(foo) information, it just looks like a number
> 8.
>
> I hacked up Sparse a bit so it works for simple expressions which
> are one token in from the c tokenizer. So:
>
> foo = kmalloc(sizeof(foo), GFP_KERNEL); => error.
> foo->bar = kmalloc(sizeof(foo->bar), GFP_KERNEL); => tricky.
>
> It's not ideal. Coccinelle is better for this.
On the other hand, Coccinelle has no idea what the size is, so it doesn't
know how important the problem is.
julia
next prev parent reply other threads:[~2012-04-21 15:13 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-20 6:47 [patch] wireless: at76c50x: allocating too much data Dan Carpenter
2012-04-20 6:47 ` Dan Carpenter
2012-04-20 8:57 ` Julian Calaby
2012-04-20 8:57 ` Julian Calaby
2012-04-20 9:14 ` Dan Carpenter
2012-04-20 9:14 ` Dan Carpenter
2012-04-20 18:14 ` Kalle Valo
2012-04-20 18:14 ` Kalle Valo
2012-04-21 12:23 ` [patch v2] " Dan Carpenter
2012-04-21 12:23 ` Dan Carpenter
2012-04-21 12:45 ` [patch] " Dan Carpenter
2012-04-21 12:45 ` Dan Carpenter
2012-04-21 13:19 ` Julia Lawall
2012-04-21 13:19 ` Julia Lawall
2012-04-21 13:51 ` Julia Lawall
2012-04-21 13:51 ` Julia Lawall
2012-04-21 14:51 ` Dan Carpenter
2012-04-21 14:51 ` Dan Carpenter
2012-04-21 14:51 ` Julia Lawall
2012-04-21 14:51 ` Julia Lawall
2012-04-21 14:59 ` Dan Carpenter
2012-04-21 14:59 ` Dan Carpenter
2012-04-21 15:12 ` Dan Carpenter
2012-04-21 15:12 ` Dan Carpenter
2012-04-21 15:13 ` Julia Lawall [this message]
2012-04-21 15:13 ` Julia Lawall
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=alpine.DEB.2.02.1204211712270.1987@hadrien \
--to=julia.lawall@lip6.fr \
--cc=dan.carpenter@oracle.com \
--cc=julian.calaby@gmail.com \
--cc=kernel-janitors@vger.kernel.org \
--cc=kvalo@adurom.com \
--cc=linux-wireless@vger.kernel.org \
--cc=linville@tuxdriver.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.