From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92D16CA9EA9 for ; Fri, 18 Oct 2019 17:38:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D0221222BD for ; Fri, 18 Oct 2019 17:38:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D0221222BD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deneb.enyo.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 802C18E0006; Fri, 18 Oct 2019 13:38:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B30A8E0003; Fri, 18 Oct 2019 13:38:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6C8A08E0006; Fri, 18 Oct 2019 13:38:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0041.hostedemail.com [216.40.44.41]) by kanga.kvack.org (Postfix) with ESMTP id 423918E0003 for ; Fri, 18 Oct 2019 13:38:32 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id A520F3489 for ; Fri, 18 Oct 2019 17:38:31 +0000 (UTC) X-FDA: 76057614822.23.heart32_2d42e0263c93e X-HE-Tag: heart32_2d42e0263c93e X-Filterd-Recvd-Size: 2176 Received: from albireo.enyo.de (albireo.enyo.de [37.24.231.21]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Fri, 18 Oct 2019 17:38:30 +0000 (UTC) Received: from [172.17.203.2] (helo=deneb.enyo.de) by albireo.enyo.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) id 1iLWCp-0001Vr-46; Fri, 18 Oct 2019 17:38:27 +0000 Received: from fw by deneb.enyo.de with local (Exim 4.92) (envelope-from ) id 1iLWCo-0005C0-0k; Fri, 18 Oct 2019 19:38:26 +0200 From: Florian Weimer To: Vlastimil Babka Cc: Dave Chinner , linux-mm@kvack.org, Mel Gorman Subject: Re: [bug, 5.2.16] kswapd/compaction null pointer crash [was Re: xfs_inode not reclaimed/memory leak on 5.2.16] References: <87pnji8cpw.fsf@mid.deneb.enyo.de> <20190930085406.GP16973@dread.disaster.area> <87o8z1fvqu.fsf@mid.deneb.enyo.de> <20190930211727.GQ16973@dread.disaster.area> <96023250-6168-3806-320a-a3468f1cd8c9@suse.cz> <87blugh452.fsf@mid.deneb.enyo.de> <3560f07e-03a7-9291-6494-e0580eeaa6bd@suse.cz> Date: Fri, 18 Oct 2019 19:38:25 +0200 In-Reply-To: <3560f07e-03a7-9291-6494-e0580eeaa6bd@suse.cz> (Vlastimil Babka's message of "Wed, 16 Oct 2019 22:03:39 +0200") Message-ID: <87sgnqc5ta.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain 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: * Vlastimil Babka: > Thanks. Looks like it's indeed here in the page_to_pfn() embedded in the > clear_pageblock_skip() expansion. We've got a wrong struct page pointer, > so page_to_section gives us a bogus value, __nr_to_section() a null > pointer, and __section_mem_map_addr then accesses it. > > Hopefully the commit [1] should address the reason why we got a wrong > page pointer. You could try cherry-picking it to your stable tree, or > wait until it appears in a (hopefully near) future stable 5.3.y (5.2 is > EOL, so it won't appear there). The commit reference appears to be missing. 8-> Due to hardware changes, I've switched back to a distribution kernel for now, so I won't see the issue in a while even if it is present in newer kernels, too. Sorry.