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Wed, 28 Oct 2020 13:49:46 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EEA1511C050; Wed, 28 Oct 2020 13:49:45 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 74E0611C04A; Wed, 28 Oct 2020 13:49:45 +0000 (GMT) Received: from pomme.local (unknown [9.145.78.110]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 28 Oct 2020 13:49:45 +0000 (GMT) Subject: Re: [PATCH v2] mm/slub: fix panic in slab_alloc_node() To: Christopher Lameter Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, nathanl@linux.ibm.com, cheloha@linux.ibm.com, mhocko@suse.com, Vlastimil Babka , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , stable@vger.kernel.org References: <7ef64e75-2150-01a9-074d-a754348683b3@suse.cz> <20201027190406.33283-1-ldufour@linux.ibm.com> From: Laurent Dufour Message-ID: <73aa614f-24e6-75d5-8173-d858a5b33fec@linux.ibm.com> Date: Wed, 28 Oct 2020 14:49:45 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-10-28_06:2020-10-26,2020-10-28 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 mlxscore=0 suspectscore=0 lowpriorityscore=0 clxscore=1015 bulkscore=0 priorityscore=1501 malwarescore=0 phishscore=0 mlxlogscore=952 adultscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010280088 Content-Transfer-Encoding: quoted-printable 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: Le 28/10/2020 =C3=A0 12:11, Christopher Lameter a =C3=A9crit=C2=A0: > On Tue, 27 Oct 2020, Laurent Dufour wrote: >=20 >> The issue is that object is not NULL while page is NULL which is odd b= ut >> may happen if the cache flush happened after loading object but before >> loading page. Thus checking for the page pointer is required too. >=20 >=20 > Ok then lets revert commit 6159d0f5c03e? The situation may occur > elsewhere too. The only other call to node_match() is in ___slab_alloc(), and the page p= ointer=20 is already checked there. So there is no real need to check it in node_match().