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From: "H. Peter Anvin" <hpa@zytor.com>
To: Andrei Warkentin <awarkentin@vmware.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] /dev/mem: Fix wrong error on accessing beyond valid memory addresses.
Date: Mon, 14 Nov 2011 14:12:35 -0800	[thread overview]
Message-ID: <4EC19253.6080201@zytor.com> (raw)
In-Reply-To: <1145760360.50519.1321308673807.JavaMail.root@zimbra-prod-mbox-2.vmware.com>

On 11/14/2011 02:11 PM, Andrei Warkentin wrote:
>>
>> EOF seems wrong to me (not as bad as EFAULT, but still wrong).
>
> Although that was what we had discussed, I do not return -EOF in the patch. As you
> mention - that would be wrong. I played around with other devices (block, actually),
> and if you attempt to read(2) beyond the end, read(2) simply returns 0, as in
> zero bytes read out. Of course, lseek(2) beyond the end should return -EINVAL, as
> well, so that is what that patch I CCd you on accomplishes.
>

0 is EOF.

This is not a block device -- comparing to block devices is pointless. 
There is no "end" to /dev/mem, so this is a totally meaningless comparison.

	-hpa



  reply	other threads:[~2011-11-14 22:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-09 23:31 [PATCH] /dev/mem: Fix wrong error on accessing beyond valid memory addresses Andrei Warkentin
2011-11-14 21:21 ` Andrei Warkentin
2011-11-14 21:59   ` H. Peter Anvin
2011-11-14 22:11     ` Andrei Warkentin
2011-11-14 22:12       ` H. Peter Anvin [this message]
2011-11-14 22:33         ` Andrei Warkentin

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