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 36412C433F5 for ; Wed, 30 Mar 2022 20:57:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A4ED66B0072; Wed, 30 Mar 2022 16:57:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9FEAA6B0073; Wed, 30 Mar 2022 16:57:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8EDC18D0001; Wed, 30 Mar 2022 16:57:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0188.hostedemail.com [216.40.44.188]) by kanga.kvack.org (Postfix) with ESMTP id 7D0036B0072 for ; Wed, 30 Mar 2022 16:57:11 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 1DD9FA6304 for ; Wed, 30 Mar 2022 20:57:11 +0000 (UTC) X-FDA: 79302262662.21.3BB6C8D Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf12.hostedemail.com (Postfix) with ESMTP id 9C9684000B for ; Wed, 30 Mar 2022 20:57:10 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id CA8F5B81E44; Wed, 30 Mar 2022 20:57:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59A4EC340EC; Wed, 30 Mar 2022 20:57:06 +0000 (UTC) Date: Wed, 30 Mar 2022 16:57:04 -0400 From: Steven Rostedt To: Zi Yan Cc: Linus Torvalds , LKML , Mel Gorman , David Hildenbrand , Vlastimil Babka , Mike Rapoport , Oscar Salvador , Andrew Morton , Linux-MM Subject: Re: [BUG] Crash on x86_32 for: mm: page_alloc: avoid merging non-fallbackable pageblocks with others Message-ID: <20220330165704.730be2b5@gandalf.local.home> In-Reply-To: References: <20220330154208.71aca532@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: Authentication-Results: imf12.hostedemail.com; dkim=none; spf=pass (imf12.hostedemail.com: domain of "SRS0=X/cO=UJ=goodmis.org=rostedt@kernel.org" designates 145.40.68.75 as permitted sender) smtp.mailfrom="SRS0=X/cO=UJ=goodmis.org=rostedt@kernel.org"; dmarc=none X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 9C9684000B X-Stat-Signature: f5ic1qtqz5qasj8dzsgomgeuctjxsgtr X-HE-Tag: 1648673830-299103 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 Wed, 30 Mar 2022 16:29:28 -0400 Zi Yan wrote: > In the original code, it will jump back to continue_merging and still tries > to find the buddy. The crash means the found buddy is not valid, since its > pageblock migratetype is NULL. That seems to suggest the physical memory > range is not aligned to MAX_ORDER_NR_PAGES, which should not be the case. > But if (!page_is_buddy(page, buddy, order)) prevents further buddy merging. > I must be missing something. Not sure if this matters or not, but my kernel command line has: crashkernel=256M Could that have caused this to break? -- Steve