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=-1.0 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 7E889C32792 for ; Mon, 30 Sep 2019 21:44:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C3C821924 for ; Mon, 30 Sep 2019 21:44:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732157AbfI3VoF (ORCPT ); Mon, 30 Sep 2019 17:44:05 -0400 Received: from albireo.enyo.de ([37.24.231.21]:56896 "EHLO albireo.enyo.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728819AbfI3VoF (ORCPT ); Mon, 30 Sep 2019 17:44:05 -0400 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 1iF3Sc-0006PF-4d; Mon, 30 Sep 2019 21:44:02 +0000 Received: from fw by deneb.enyo.de with local (Exim 4.92) (envelope-from ) id 1iF3RG-0001ar-Am; Mon, 30 Sep 2019 23:42:38 +0200 From: Florian Weimer To: Dave Chinner Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org 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> Date: Mon, 30 Sep 2019 23:42:38 +0200 In-Reply-To: <20190930211727.GQ16973@dread.disaster.area> (Dave Chinner's message of "Tue, 1 Oct 2019 07:17:27 +1000") Message-ID: <87ftkdfokx.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org * Dave Chinner: >> [ 4001.238446] Call Trace: >> [ 4001.238450] __reset_isolation_suitable+0x9b/0x120 >> [ 4001.238453] reset_isolation_suitable+0x3b/0x40 >> [ 4001.238456] kswapd+0x98/0x300 >> [ 4001.238460] ? wait_woken+0x80/0x80 >> [ 4001.238463] kthread+0x114/0x130 >> [ 4001.238465] ? balance_pgdat+0x450/0x450 >> [ 4001.238467] ? kthread_park+0x80/0x80 >> [ 4001.238470] ret_from_fork+0x1f/0x30 > > Ok, so the memory compaction code has had a null pointer dereference > which has killed kswapd. memory reclaim is going to have serious > problems from this point on as kswapd does most of the reclaim. Sorry, no. OpenVPN opened a tun device at the same time (same second), and udevd reacted to that, but that's it. I also double-checked, and there haven't been any recent previous occurrences of that crash.