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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85497C433F5 for ; Tue, 12 Apr 2022 21:18:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E30846B0072; Tue, 12 Apr 2022 17:18:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DDF226B0073; Tue, 12 Apr 2022 17:18:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CA7016B0074; Tue, 12 Apr 2022 17:18:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0113.hostedemail.com [216.40.44.113]) by kanga.kvack.org (Postfix) with ESMTP id BA0786B0072 for ; Tue, 12 Apr 2022 17:18:00 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 57496183E6C96 for ; Tue, 12 Apr 2022 21:18:00 +0000 (UTC) X-FDA: 79349489520.27.58BCD6C Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf30.hostedemail.com (Postfix) with ESMTP id 4A17180008 for ; Tue, 12 Apr 2022 21:17:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=cyVUQoF5FLTGwJesMJ+yRkVIcAvwZ1zngJkSXYEZEGQ=; b=UwYHSgvbWSCe4hdu6JlE+pm8qv JHQ1/ncPQlLB8arQQ+NKk/zUTQ49AdGC2JvwBuQnVoLeBtlzUohb8EGBkqP3Aj5GwKUllmOABLofu nJGC50eEyhXehObrFHzsXDsyVeUqmgvYK2Gi+4Vza1l8KsXJ9EZPCz/x9ZhTqZVk4hdsMYWn/K/Mn veKVfx7PCj7Z7cvPXDlGX0UOvP5DTb3uH5D5tspjoRh+sCxWEWvbFe1cezmwmUE3lCWgmpBvTJA9E FS9xRv9GX8FgyUMfsFS74hPDNYZy0tBS4nGo7yn4AZAmgmqSZ0hGJF8Gnxsw6NRq9leh5uTjvvea/ bgNCIkzA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1neNta-00DhXR-V7; Tue, 12 Apr 2022 21:17:54 +0000 Date: Tue, 12 Apr 2022 22:17:54 +0100 From: Matthew Wilcox To: Andrew Morton Cc: bugzilla-daemon@kernel.org, parag.lkml@gmail.com, linux-mm@kvack.org, dri-devel@lists.freedesktop.org Subject: Re: [Bug 215807] Bad page state in process systemd-udevd Message-ID: References: <20220412140804.e73d55d5d192f2198c9278ec@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220412140804.e73d55d5d192f2198c9278ec@linux-foundation.org> Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=UwYHSgvb; spf=none (imf30.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Stat-Signature: 9exi7rqq3q1tnzpoh3dxiy9xaturx935 X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 4A17180008 X-HE-Tag: 1649798279-820832 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, Apr 12, 2022 at 02:08:04PM -0700, Andrew Morton wrote: > hm, that's my third `bad page' report in three emails. But I'm not > seeing a pattern - this one might be a DRM thing. I noticed it was an order-9 page and was set to take responsibility for it, but it's clearly not a filesystem page, but a DRM page. Let me help decode this for the benefit of the DRM folks. > > [ 8.453363] amdgpu: Topology: Add CPU node > > [ 8.467169] BUG: Bad page state in process systemd-udevd pfn:11b403 > > [ 8.467180] fbcon: Taking over console > > [ 8.467188] page:000000002cc06944 refcount:0 mapcount:0 > > mapping:0000000000000000 index:0x3 pfn:0x11b403 > > [ 8.467195] head:00000000aa25e58e order:9 compound_mapcount:0 > > compound_pincount:0 > > [ 8.467198] flags: 0x17ffffc0010000(head|node=0|zone=2|lastcpupid=0x1fffff) > > [ 8.467205] raw: 0017ffffc0000000 fffff2da846d0001 fffff2da846d00c8 > > 0000000000000000 > > [ 8.467208] raw: 0000000000000000 0000000000000000 00000000ffffffff > > 0000000000000000 > > [ 8.467210] head: 0017ffffc0010000 0000000000000000 dead000000000122 > > 0000000000000000 > > [ 8.467212] head: 0000000000000000 0000000000000000 00000000ffffffff > > 0000000000000000 > > [ 8.467214] page dumped because: corrupted mapping in tail page Tail pages are all supposed to have page->mapping == TAIL_MAPPING (0x400 + POISON_POINTER_DELTA). This one has page->mapping == NULL. I say "all", but tail pages 1 and 2 aren't checked because those get other useful things stored in them instead. This is tail page number 3, so it's the first one checked. So DRM has probably been overly enthusiastic about cleaning up something. Hope that's helpful!