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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 17EB3C54FD0 for ; Mon, 27 Apr 2020 02:03:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E82B8206B9 for ; Mon, 27 Apr 2020 02:03:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="d8cQhN9h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726450AbgD0CDF (ORCPT ); Sun, 26 Apr 2020 22:03:05 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:51555 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726327AbgD0CDE (ORCPT ); Sun, 26 Apr 2020 22:03:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587952982; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=v8IFSlr9wk6PnyUzpFzR48ViDPJ0s7W1u3H0V53GluQ=; b=d8cQhN9hOKBk09jvHvC9RP4DkL5y6/+9I16xp2ph0JPNmTisFiWdX9sfG1lvpXFJlwVSEA k6dr2UOONTyIUJoZAIUKZbI8u8wZa+J2d06lsQqcWq0FYSyNgpezFmQTG9igaxWTInEUKv e8nTvpR/vW2a+2OKsfI68hj7M5NEppA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-448-N7-FcSTOP6ivGEwrnC56Ig-1; Sun, 26 Apr 2020 22:02:28 -0400 X-MC-Unique: N7-FcSTOP6ivGEwrnC56Ig-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0417C835B40; Mon, 27 Apr 2020 02:02:27 +0000 (UTC) Received: from llong.com (ovpn-112-228.rdu2.redhat.com [10.10.112.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0D351610B0; Mon, 27 Apr 2020 02:02:21 +0000 (UTC) From: Waiman Long To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Kees Cook Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Changbin Du , Waiman Long Subject: [PATCH] mm/slub: Fix incorrect checkings of s->offset Date: Sun, 26 Apr 2020 22:02:12 -0400 Message-Id: <20200427020212.5222-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In a couple of places in the slub memory allocator, the code uses "s->offset" as a check to see if the free pointer is put right after the object. That check is no longer true with commit 3202fa62fb43 ("slub: relocate freelist pointer to middle of object"). As a result, echoing "1" into the validate sysfs file, e.g. of dentry, may cause a bunch of "Freepointer corrupt" error reports to appear with the system in panic afterwards. To fix it, use the check "s->offset == s->inuse" instead. Fixes: 3202fa62fb43 ("slub: relocate freelist pointer to middle of object") Signed-off-by: Waiman Long --- mm/slub.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 0e736d66bb42..99952d01e7e0 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -556,10 +556,8 @@ static struct track *get_track(struct kmem_cache *s, void *object, { struct track *p; - if (s->offset) - p = object + s->offset + sizeof(void *); - else - p = object + s->inuse; + p = object + s->inuse + + ((s->offset == s->inuse) ? sizeof(void *) : 0); return p + alloc; } @@ -693,10 +691,8 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) print_section(KERN_ERR, "Redzone ", p + s->object_size, s->inuse - s->object_size); - if (s->offset) - off = s->offset + sizeof(void *); - else - off = s->inuse; + off = s->inuse + + ((s->offset == s->inuse) ? sizeof(void *) : 0); if (s->flags & SLAB_STORE_USER) off += 2 * sizeof(struct track); @@ -790,7 +786,7 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page, * object address * Bytes of the object to be managed. * If the freepointer may overlay the object then the free - * pointer is the first word of the object. + * pointer is at the middle of the object. * * Poisoning uses 0x6b (POISON_FREE) and the last byte is * 0xa5 (POISON_END) @@ -826,7 +822,7 @@ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) { unsigned long off = s->inuse; /* The end of info */ - if (s->offset) + if (s->offset == s->inuse) /* Freepointer is placed after the object. */ off += sizeof(void *); @@ -915,7 +911,7 @@ static int check_object(struct kmem_cache *s, struct page *page, check_pad_bytes(s, page, p); } - if (!s->offset && val == SLUB_RED_ACTIVE) + if ((s->offset != s->inuse) && val == SLUB_RED_ACTIVE) /* * Object and freepointer overlap. Cannot check * freepointer while object is allocated. -- 2.18.1