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[156.151.31.85]) by mx.google.com with ESMTPS id k7si14655183qte.258.2019.04.15.03.26.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 15 Apr 2019 03:26:14 -0700 (PDT) Received-SPF: pass (google.com: domain of william.kucharski@oracle.com designates 156.151.31.85 as permitted sender) client-ip=156.151.31.85; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=LnCj7QAV; spf=pass (google.com: domain of william.kucharski@oracle.com designates 156.151.31.85 as permitted sender) smtp.mailfrom=william.kucharski@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3FAEJFu142919; Mon, 15 Apr 2019 10:26:06 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2018-07-02; bh=/BPNJ5Z0meskioHq9nZpVNtN1OnHlR0EfY4j+0WKJwI=; b=LnCj7QAVeeMEZGQVmEeSgyntjpqoWpolMGyBEUMeSHjlESTL3KxoyiWf3zHLU0lDWkFp he0YsF5X+TQqKIpqM6D+V3JxM+jUuYeiGvanTZpiFqSTheXUlYiTrwljpQrJ6YQNFu35 Jr4GdOSGOmNv6vYDFYYoIlj5ndy4Tx0goTKww2zsxbnB9/N6rFoCpktVKSnLO1HMOhX7 /Cxy3iutUiny8p3EzSNoBYaQG/tVpwsbAX1PY1Rz0am87VRtCNFGI6/rtZF5BfxZdKaO 59gIJL8k3bRJ6cHvCVmxNVtdUTh1oAf2Ko182ADs5iPkSB1u2q6MsMSSHrttDUJ+OB0T xg== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 2rusnektxd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 15 Apr 2019 10:26:06 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3FAOS2w132610; Mon, 15 Apr 2019 10:26:06 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 2rubq5njva-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 15 Apr 2019 10:26:06 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x3FAQ3Yv006777; Mon, 15 Apr 2019 10:26:03 GMT Received: from [192.168.0.110] (/73.243.10.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 15 Apr 2019 03:26:03 -0700 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.8\)) Subject: Re: [PATCH v2] hugetlbfs: fix protential null pointer dereference From: William Kucharski In-Reply-To: Date: Mon, 15 Apr 2019 04:26:02 -0600 Cc: Michal Hocko , Yufen Yu , linux-mm@kvack.org, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com Content-Transfer-Encoding: 7bit Message-Id: References: <20190411035318.32976-1-yuyufen@huawei.com> <20190411081900.GP10383@dhcp22.suse.cz> <20190411182220.GD10383@dhcp22.suse.cz> To: Mike Kravetz X-Mailer: Apple Mail (2.3445.104.8) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9227 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904150073 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9227 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904150073 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 Apr 11, 2019, at 12:40 PM, Mike Kravetz wrote: > > You are right. That would make more sense. It has been a while since I > looked into that code and unfortunately I did not save notes. I'll do some > research to come up with an appropriate explanation/comment. I also like the idea of a comment rather than code here. Zero run time impact and more importantly it instantly explains to everyone why this case is different rather than just adding the check for the sake of uniformity.