From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1753228AbcJCM3F (ORCPT <rfc822;w@1wt.eu>);
        Mon, 3 Oct 2016 08:29:05 -0400
Received: from mout.web.de ([217.72.192.78]:55605 "EHLO mout.web.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1752426AbcJCM2r (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 3 Oct 2016 08:28:47 -0400
Subject: Re: [PATCH v2 2/2] KVM: s390: Use memdup_user() rather than
 duplicating code
To: Geert Uytterhoeven <geert@linux-m68k.org>
References: <82b84c9c-38a4-4d17-910f-312668dbae01@users.sourceforge.net>
 <bb710b21-d8c4-e172-63d4-b46c80645cb3@users.sourceforge.net>
 <ddb2bbd9-757b-fc62-8642-ce827a7a666d@de.ibm.com>
 <e72e9854-443b-7033-d674-8a2d237600ca@users.sourceforge.net>
 <c86f7520-885e-2829-ae9c-b81caa898e84@users.sourceforge.net>
 <CAMuHMdVX6RKZYQyOrX35D+EKoRH6ZFAkyiC=BKnyKtE1Ph4t8g@mail.gmail.com>
Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org,
        =?UTF-8?Q?Christian_Borntr=c3=a4ger?= <borntraeger@de.ibm.com>,
        Cornelia Huck <cornelia.huck@de.ibm.com>,
        David Hildenbrand <dahi@linux.vnet.ibm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>, kernel-janitors@vger.kernel.org,
        Julia Lawall <julia.lawall@lip6.fr>, Walter Harms <wharms@bfs.de>
From: SF Markus Elfring <elfring@users.sourceforge.net>
Message-ID: <73d5a586-2178-a311-f19c-c16c6e8cbb22@users.sourceforge.net>
Date: Mon, 3 Oct 2016 14:28:24 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.4.0
MIME-Version: 1.0
In-Reply-To: <CAMuHMdVX6RKZYQyOrX35D+EKoRH6ZFAkyiC=BKnyKtE1Ph4t8g@mail.gmail.com>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
X-Provags-ID: V03:K0:ptWQ9Aq6t4oX/ZNR9XnZV5v3qt3EvxhhYhlAlSrTFfqnBBKuGO6
 Vsw1fQejJOs6LPnbzazqGfD8GinjBzhfLdItSQsG00RImDD5W8PDbl9XPuuUj7w0wQnJkTh
 p/d/DIcP0OXAZPK9ghjcmjcmF6GUqQhqjr6Fv2/MySMBFCt2j1tOsqb0/J1IO2dlPxHoOvJ
 v/+42YRGPlGqPkvPkeX9g==
X-UI-Out-Filterresults: notjunk:1;V01:K0:DImq34X3XbA=:J5Fk+PpoYu6bV8MrDOHJWr
 7t4fsr0Yb7cc3+hy5qAaIzof6Uuf9SB+n7cH68IBkmiYRSTlpziiLqkYWilrMPe8EuMeceWPl
 q7ADx748SuS2noqKa0veDXYOw6AzyDGdZ5WJTvDFy8rXljxCtcENzwUX/wkSkYQVOBmG4nJYZ
 R/txUbfAvChoEwB9uAuu8KixEZi75CC+gwHocGbJVwizLN5A2s4LF3Iwrz5rZucToojM9tDce
 fk+cLjuQAYticdTu9xUv3W7uluSjgAY/bN7iBPPtV4Fw9I5wI5G9JoUZyj4rq0yBanq7Aehhu
 Kn7qjmW4UlfY3vAAMcg/0PQ9rK3dYwnpEY1p/74ETF8nSrVir0qBxMeutlb/lKRnDcbce2hdZ
 75Pow8kxcDX4UG/KvywWwR2aeGTJt8Z/nLOiVDwMuk+EpiHoLqPsLpOSzJwNEM5JopUXtbdwH
 2iS78mInWIqTQK+/eoCGBRXTDfF8RyTHE3dni8sq/3+RHeWQsqeXy2lCpQk0lW+gqtPlR7z00
 LUU36nok1BLkiY8oA/eZLu9En8TofnlUnbxekWU/wi1LyXWdcB8UyOFcr5YiINP4Ry/T6LMNr
 025BPfh/0RcW642POGrt2eJ8neJIBxlutIn3nXGVMh2B+QuY4ddELUO/qpkTjLeYLjC2lIsQe
 PbEcysnMNKSn6GtAktG051QlVXdxW1qLFM73q3YJh6TCdN7k+6mWrp2y1H2tT8u6JZJ51fG0r
 njIxRAuPCwaM2YH4w3/LJAXVvDZAgg9xD9LsZ4HmdB5EJ93UXE6dELmawnIZJjCyOlWumP8xD
 A4oAcM2
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

>> -       if (!bp_data) {
>> -               ret = -ENOMEM;
>> -               goto error;
>> -       }
>> -
>> -       if (copy_from_user(bp_data,
>> -                          dbg->arch.hw_bp,
>> -                          sizeof(*bp_data) * dbg->arch.nr_hw_bp)) {
>> -               ret = -EFAULT;
>> -               goto error;
>> -       }
>> +       bp_data = memdup_user(dbg->arch.hw_bp,
>> +                             sizeof(*bp_data) * dbg->arch.nr_hw_bp);
> 
> ... while this would continue silently,

How do you think about to explain this information a bit more?


> and corrupt memory.

I wonder about this conclusion at the moment.

Did you notice the check "IS_ERR(bp_data)" and the corresponding reaction
in this update suggestion?

How does your feedback fit to the tag "Acked-by: Cornelia Huck"
from 2016-08-25?

Regards,
Markus