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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 41BC3C43613 for ; Fri, 21 Jun 2019 19:38:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23FAF2075E for ; Fri, 21 Jun 2019 19:38:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726129AbfFUTil (ORCPT ); Fri, 21 Jun 2019 15:38:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40234 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725947AbfFUTik (ORCPT ); Fri, 21 Jun 2019 15:38:40 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 74EA23082E21; Fri, 21 Jun 2019 19:38:40 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-40.ams2.redhat.com [10.36.116.40]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9F5D419C59; Fri, 21 Jun 2019 19:38:35 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: David Hildenbrand , Andrew Morton , Stephen Rothwell , Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-mm@kvack.org, Qian Cai Subject: [PATCH] drivers/base/memory.c: Fix "mm/memory_hotplug: Move and simplify walk_memory_blocks()" Date: Fri, 21 Jun 2019 21:38:34 +0200 Message-Id: <20190621193834.21730-1-david@redhat.com> In-Reply-To: <1561130120.5154.47.camel@lca.pw> References: <1561130120.5154.47.camel@lca.pw> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Fri, 21 Jun 2019 19:38:40 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The start and the size are 0 for online nodes without any memory. Avoid the underflow, resulting in a very long loop and soft lockups. Cc: Andrew Morton Cc: Stephen Rothwell Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: linux-mm@kvack.org Reported-by: Qian Cai Signed-off-by: David Hildenbrand --- @Andrew, Stephen - sorry for the noise *again*. Feel feel to either apply this patch or drop the respective patches for now. --- drivers/base/memory.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 972c5336bebf..7595a4f0068f 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -868,6 +868,9 @@ int walk_memory_blocks(unsigned long start, unsigned long size, unsigned long block_id; int ret = 0; + if (!size) + return 0; + for (block_id = start_block_id; block_id <= end_block_id; block_id++) { mem = find_memory_block_by_id(block_id); if (!mem) -- 2.21.0