Date: Sat, 21 Apr 2012 15:45:23 +0300
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Kalle Valo <kvalo@adurom.com>
Cc: 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
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On Fri, Apr 20, 2012 at 09:14:44PM +0300, Kalle Valo wrote:
> Dan Carpenter <dan.carpenter@oracle.com> writes:
> 
> > On Fri, Apr 20, 2012 at 06:57:00PM +1000, Julian Calaby wrote:
> >> > - ? ? ? struct mib_local *m = kmalloc(sizeof(struct mib_phy), GFP_KERNEL);
> >> > + ? ? ? struct mib_local *m = kmalloc(sizeof(struct mib_local), GFP_KERNEL);
> >> 
> >> Would it be better practice to use sizeof(*m)?
> >> 
> >
> > That was my temptation as well...  But I decided to make it match
> > with the surrounding code.  I'm happy to resend if people want.
> 
> IMHO sizeof(*m) is better and I tend to use it.
> 
> Related to this: I have a bad habit of sometimes dropping '*' from
> sizeof()? Is there a tool which could spot that?
> 

That's what I was working on for Smatch when I sent this patch.

The odd thing is that I can't find any bugs like this in the kernel.
If sizeof(foo) is less than sizeof(*foo), which is probably the
normal case, then these get caught early on in testing.

Still I think people must have done manual audits as well...  It
feels too clean to be natural.

regards,
dan carpenter