From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753242AbdBTNYk (ORCPT ); Mon, 20 Feb 2017 08:24:40 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:51697 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752767AbdBTNYi (ORCPT ); Mon, 20 Feb 2017 08:24:38 -0500 Date: Mon, 20 Feb 2017 14:24:24 +0100 From: Heiko Carstens To: Elena Reshetova Cc: linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, x86@kernel.org, sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, tony.luck@intel.com, hpa@zytor.com, Hans Liljestrand , Kees Cook , David Windsor Subject: Re: [PATCH 1/4] s390: convert debug_info.ref_count from atomic_t to refcount_t References: <1487588781-15123-1-git-send-email-elena.reshetova@intel.com> <1487588781-15123-2-git-send-email-elena.reshetova@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1487588781-15123-2-git-send-email-elena.reshetova@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17022013-0028-0000-0000-000002AE3542 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17022013-0029-0000-0000-00002270244C Message-Id: <20170220132424.GA5656@osiris> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-02-20_12:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1702200132 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 20, 2017 at 01:06:18PM +0200, Elena Reshetova wrote: > refcount_t type and corresponding API should be > used instead of atomic_t when the variable is used as > a reference counter. This allows to avoid accidental > refcounter overflows that might lead to use-after-free > situations. > > Signed-off-by: Elena Reshetova > Signed-off-by: Hans Liljestrand > Signed-off-by: Kees Cook > Signed-off-by: David Windsor > --- > arch/s390/include/asm/debug.h | 3 ++- > arch/s390/kernel/debug.c | 8 ++++---- > 2 files changed, 6 insertions(+), 5 deletions(-) I can only see a pull request from Ingo a couple of hours ago for Peter's refcount code. So the refcount code is not merged yet. It would have been good if you would have waited until it is really merged to avoid confusion. > @@ -361,7 +361,7 @@ debug_info_create(const char *name, int pages_per_area, int nr_areas, > debug_area_last = rc; > rc->next = NULL; > > - debug_info_get(rc); > + refcount_set(&rc->ref_count, 1); This is not wrong, but I will remove this hunk before applying your patch, since this doesn't look like an obvious correct change at first glance. Thanks, Heiko