From patchwork Mon Aug 24 13:06:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eugeniu Rosca X-Patchwork-Id: 264921 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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 8DBDFC433DF for ; Mon, 24 Aug 2020 13:07:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DAC5214F1 for ; Mon, 24 Aug 2020 13:07:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726008AbgHXNHR (ORCPT ); Mon, 24 Aug 2020 09:07:17 -0400 Received: from smtp1.de.adit-jv.com ([93.241.18.167]:43639 "EHLO smtp1.de.adit-jv.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725926AbgHXNHR (ORCPT ); Mon, 24 Aug 2020 09:07:17 -0400 Received: from localhost (smtp1.de.adit-jv.com [127.0.0.1]) by smtp1.de.adit-jv.com (Postfix) with ESMTP id A30383C0579; Mon, 24 Aug 2020 15:07:13 +0200 (CEST) Received: from smtp1.de.adit-jv.com ([127.0.0.1]) by localhost (smtp1.de.adit-jv.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rS9E865DscdH; Mon, 24 Aug 2020 15:07:08 +0200 (CEST) Received: from HI2EXCH01.adit-jv.com (hi2exch01.adit-jv.com [10.72.92.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by smtp1.de.adit-jv.com (Postfix) with ESMTPS id 920423C0016; Mon, 24 Aug 2020 15:07:08 +0200 (CEST) Received: from lxhi-065.adit-jv.com (10.72.94.3) by HI2EXCH01.adit-jv.com (10.72.92.24) with Microsoft SMTP Server (TLS) id 14.3.487.0; Mon, 24 Aug 2020 15:07:08 +0200 From: Eugeniu Rosca To: Andrew Morton , Dongli Zhang CC: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , , , , Eugeniu Rosca , Eugeniu Rosca Subject: [PATCH v2] mm: slub: fix conversion of freelist_corrupted() Date: Mon, 24 Aug 2020 15:06:43 +0200 Message-ID: <20200824130643.10291-1-erosca@de.adit-jv.com> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 X-Originating-IP: [10.72.94.3] Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Commit 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in deactivate_slab()") suffered an update when picked up from LKML [1]. Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()' created a no-op statement. Fix it by sticking to the behavior intended in the original patch [1]. In addition, make freelist_corrupted() immune to passing NULL instead of &freelist. The issue has been spotted via static analysis and code review. [1] https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zhang@oracle.com/ Fixes: 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in deactivate_slab()") Cc: Andrew Morton Cc: Dongli Zhang Cc: Signed-off-by: Eugeniu Rosca --- v2: - Address the review finding from Dongli Zhang in: https://lore.kernel.org/linux-mm/f93a9f06-8608-6f28-27c0-b17f86dca55b@oracle.com/ -------8<------- This is good to me. However, this would confuse people when CONFIG_SLUB_DEBUG is not defined. While reading the source code, people may be curious why to reset freelist when CONFIG_SLUB_DEBUG is even not defined. -------8<------- v1: - https://lore.kernel.org/linux-mm/20200811124656.10308-1-erosca@de.adit-jv.com/ mm/slub.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 68c02b2eecd9..d4177aecedf6 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -672,12 +672,12 @@ static void slab_fix(struct kmem_cache *s, char *fmt, ...) } static bool freelist_corrupted(struct kmem_cache *s, struct page *page, - void *freelist, void *nextfree) + void **freelist, void *nextfree) { if ((s->flags & SLAB_CONSISTENCY_CHECKS) && - !check_valid_pointer(s, page, nextfree)) { - object_err(s, page, freelist, "Freechain corrupt"); - freelist = NULL; + !check_valid_pointer(s, page, nextfree) && freelist) { + object_err(s, page, *freelist, "Freechain corrupt"); + *freelist = NULL; slab_fix(s, "Isolate corrupted freechain"); return true; } @@ -1494,7 +1494,7 @@ static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) {} static bool freelist_corrupted(struct kmem_cache *s, struct page *page, - void *freelist, void *nextfree) + void **freelist, void *nextfree) { return false; } @@ -2184,7 +2184,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page, * 'freelist' is already corrupted. So isolate all objects * starting at 'freelist'. */ - if (freelist_corrupted(s, page, freelist, nextfree)) + if (freelist_corrupted(s, page, &freelist, nextfree)) break; do {