linux-kernel - Re: [PATCH 01/24] fix default __strnlen

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Message-ID: <4E60167C.3090500@gmail.com>
Date:	Fri, 02 Sep 2011 09:34:20 +1000
From:	Ryan Mallon <rmallon@...il.com>
To:	Mark Salter <msalter@...hat.com>
CC:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/24] fix default __strnlen_user macro

On 02/09/11 05:23, Mark Salter wrote:
> On Thu, 2011-09-01 at 11:54 +1000, Ryan Mallon wrote:
>> It should either be changed as I suggested, or the comment in uaccess.h
>> should be updated to reflect the actual behaviour of the function
>> (stating that it returns n + 1 in the case where n is reached). Either
>> way, its probably worth doing a quick check through the arch specific
>> versions to see what their behaviour really is. It looks like there are
>> potentially some subtle bugs at the callsites.
> I think commenting it in uaccess.h is the only sane way to go. Changing
> the semantics means changing all the arch-specific versions, most of
> which are asm code and changing most, if not all callsites. All of the
> arch-specific versions I looked at include the NULL count.
>

Agreed. Add a note to the comment that callers should check for a return 
value > n.

~Ryan


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