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Tue, 12 Jul 2022 19:27:55 +0000 (GMT) Received: from osiris (unknown [9.145.52.105]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Tue, 12 Jul 2022 19:27:55 +0000 (GMT) Date: Tue, 12 Jul 2022 21:27:53 +0200 From: Heiko Carstens To: Claudio Imbrenda Cc: Steffen Eiden , Alexander Gordeev , Christian Borntraeger , Janosch Frank , Vasily Gorbik , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nrb@linux.ibm.com Subject: Re: [PATCH 1/3] s390/cpufeature: rework to allow more than only hwcap bits Message-ID: References: <20220712105220.325010-1-seiden@linux.ibm.com> <20220712105220.325010-2-seiden@linux.ibm.com> <20220712184619.45edd420@p-imbrenda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220712184619.45edd420@p-imbrenda> X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: edzKj_LzbgK8bX0Wc0YOlwfKFcO075uU X-Proofpoint-GUID: edzKj_LzbgK8bX0Wc0YOlwfKFcO075uU X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-07-12_12,2022-07-12_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 adultscore=0 mlxscore=0 suspectscore=0 clxscore=1011 lowpriorityscore=0 priorityscore=1501 phishscore=0 mlxlogscore=677 spamscore=0 impostorscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2206140000 definitions=main-2207120077 ARC-Seal: i=1; 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dkim=pass header.d=ibm.com header.s=pp1 header.b=l7xNSmRz; dmarc=pass (policy=none) header.from=ibm.com; spf=pass (imf03.hostedemail.com: domain of hca@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=hca@linux.ibm.com X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1657654082-856338 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Jul 12, 2022 at 06:46:19PM +0200, Claudio Imbrenda wrote: > > +int cpu_have_feature(unsigned int num) > > +{ > > + struct s390_cpu_feature *feature; > > + > > + feature = &s390_cpu_features[num]; > > I would put some check to make sure you are going past the end of the > array. > > Maybe something like > > if (num >= MAX_CPU_FEATURES) { > WARN(1, "Invalid feature %d", num); > return 0; That makes sense. I would go for a simple if (WARN_ON_ONCE(num >= MAX_CPU_FEATURES)) return 0;