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=-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 02062C433DF for ; Mon, 24 Aug 2020 13:08:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BF4922074D for ; Mon, 24 Aug 2020 13:08:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF4922074D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=de.adit-jv.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4B6EC8D001F; Mon, 24 Aug 2020 09:08:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 466AC8D0007; Mon, 24 Aug 2020 09:08:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 37CD58D001F; Mon, 24 Aug 2020 09:08:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 228EF8D0007 for ; Mon, 24 Aug 2020 09:08:40 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id D2809180AD81D for ; Mon, 24 Aug 2020 13:08:39 +0000 (UTC) X-FDA: 77185491558.20.grass84_2a0ba8327053 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 65FBF180C1465 for ; Mon, 24 Aug 2020 13:07:17 +0000 (UTC) X-HE-Tag: grass84_2a0ba8327053 X-Filterd-Recvd-Size: 4585 Received: from smtp1.de.adit-jv.com (smtp1.de.adit-jv.com [93.241.18.167]) by imf02.hostedemail.com (Postfix) with ESMTP for ; Mon, 24 Aug 2020 13:07:16 +0000 (UTC) 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 Content-Type: text/plain X-Originating-IP: [10.72.94.3] X-Rspamd-Queue-Id: 65FBF180C1465 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 Content-Transfer-Encoding: quoted-printable 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: Commit 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in deactivate_slab()") suffered an update when picked up from LKML [1]. Specifically, relocating 'freelist =3D 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 defin= ed. While reading the source code, people may be curious why to reset free= list 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 *fm= t, ...) } =20 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 =3D NULL; + !check_valid_pointer(s, page, nextfree) && freelist) { + object_err(s, page, *freelist, "Freechain corrupt"); + *freelist =3D 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) {} =20 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, s= truct 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; =20 do { --=20 2.28.0