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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85883C433F5 for ; Mon, 11 Apr 2022 15:34:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243251AbiDKPgm (ORCPT ); Mon, 11 Apr 2022 11:36:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348021AbiDKPgg (ORCPT ); Mon, 11 Apr 2022 11:36:36 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E8D114085 for ; Mon, 11 Apr 2022 08:34:20 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id AF607615CA for ; Mon, 11 Apr 2022 15:34:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99FE0C385A4; Mon, 11 Apr 2022 15:34:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649691259; bh=dn/qBlMxmKMU+iriGNLa+Z59Guau+hpPaFTEgzsKmHQ=; h=Subject:To:Cc:From:Date:From; b=pEtxVXa3BVWtlekTV1a34uPkUt12V96FSg8ehuLPDzTvGFwd011fBomlw5dZQaXjd HgaCdglBI6kXEk3uvangvELL4mPwsm+6qWBvNUOfYPXJG6DHYsPgnMBHayg6dgNet0 eo7pJ+819ksysGYr9P+Pe0DPOj+L0yYJrNxn0Fj4= Subject: FAILED: patch "[PATCH] mm/sparsemem: fix 'mem_section' will never be NULL gcc 12" failed to apply to 4.9-stable tree To: longman@redhat.com, akpm@linux-foundation.org, aquini@redhat.com, jforbes@redhat.com, kirill.shutemov@linux.intel.com, mingo@kernel.org, torvalds@linux-foundation.org Cc: From: Date: Mon, 11 Apr 2022 17:34:16 +0200 Message-ID: <1649691256214220@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From a431dbbc540532b7465eae4fc8b56a85a9fc7d17 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Fri, 8 Apr 2022 13:09:01 -0700 Subject: [PATCH] mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning The gcc 12 compiler reports a "'mem_section' will never be NULL" warning on the following code: static inline struct mem_section *__nr_to_section(unsigned long nr) { #ifdef CONFIG_SPARSEMEM_EXTREME if (!mem_section) return NULL; #endif if (!mem_section[SECTION_NR_TO_ROOT(nr)]) return NULL; : It happens with CONFIG_SPARSEMEM_EXTREME off. The mem_section definition is #ifdef CONFIG_SPARSEMEM_EXTREME extern struct mem_section **mem_section; #else extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; #endif In the !CONFIG_SPARSEMEM_EXTREME case, mem_section is a static 2-dimensional array and so the check "!mem_section[SECTION_NR_TO_ROOT(nr)]" doesn't make sense. Fix this warning by moving the "!mem_section[SECTION_NR_TO_ROOT(nr)]" check up inside the CONFIG_SPARSEMEM_EXTREME block and adding an explicit NR_SECTION_ROOTS check to make sure that there is no out-of-bound array access. Link: https://lkml.kernel.org/r/20220331180246.2746210-1-longman@redhat.com Fixes: 3e347261a80b ("sparsemem extreme implementation") Signed-off-by: Waiman Long Reported-by: Justin Forbes Cc: "Kirill A . Shutemov" Cc: Ingo Molnar Cc: Rafael Aquini Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 962b14d403e8..46ffab808f03 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1397,13 +1397,16 @@ static inline unsigned long *section_to_usemap(struct mem_section *ms) static inline struct mem_section *__nr_to_section(unsigned long nr) { + unsigned long root = SECTION_NR_TO_ROOT(nr); + + if (unlikely(root >= NR_SECTION_ROOTS)) + return NULL; + #ifdef CONFIG_SPARSEMEM_EXTREME - if (!mem_section) + if (!mem_section || !mem_section[root]) return NULL; #endif - if (!mem_section[SECTION_NR_TO_ROOT(nr)]) - return NULL; - return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; + return &mem_section[root][nr & SECTION_ROOT_MASK]; } extern size_t mem_section_usage_size(void);