From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f71.google.com (mail-lf0-f71.google.com [209.85.215.71]) by kanga.kvack.org (Postfix) with ESMTP id 62A9C6B0038 for ; Fri, 19 Aug 2016 08:45:12 -0400 (EDT) Received: by mail-lf0-f71.google.com with SMTP id 33so30779199lfw.1 for ; Fri, 19 Aug 2016 05:45:12 -0700 (PDT) Received: from outbound-smtp06.blacknight.com (outbound-smtp06.blacknight.com. [81.17.249.39]) by mx.google.com with ESMTPS id 131si3846933wma.114.2016.08.19.05.45.11 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 19 Aug 2016 05:45:11 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp06.blacknight.com (Postfix) with ESMTPS id C1EC398A93 for ; Fri, 19 Aug 2016 12:45:10 +0000 (UTC) Date: Fri, 19 Aug 2016 13:45:08 +0100 From: Mel Gorman Subject: Re: [PATCH] mm: Add WARN_ON for possibility of infinite loop if empty lists in free_pcppages_bulk' Message-ID: <20160819124508.GM8119@techsingularity.net> References: <1471608918-5101-1-git-send-email-pagupta@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1471608918-5101-1-git-send-email-pagupta@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Pankaj Gupta Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz, riel@redhat.com, hannes@cmpxchg.org, iamjoonsoo.kim@lge.com, kirill.shutemov@linux.intel.com, izumi.taku@jp.fujitsu.com On Fri, Aug 19, 2016 at 05:45:18PM +0530, Pankaj Gupta wrote: > While debugging issue in realtime kernel i found a scenario > which resulted in infinite loop resulting because of empty pcp->lists > and valid 'to_free' value. This patch is to add 'WARN_ON' in function > 'free_pcppages_bulk' if there is possibility of infinite loop because > of any bug in code. > What was the bug that allowed this situation to occur? It would imply the pcp count was somehow out of sync. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org