Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754142AbdHKWCs (ORCPT ); Fri, 11 Aug 2017 18:02:48 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33636 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754111AbdHKWCp (ORCPT ); Fri, 11 Aug 2017 18:02:45 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthew Dawson , Andrey Ryabinin , Andrew Morton , Linus Torvalds , Andrii Bordunov Subject: [PATCH 4.4 13/15] mm/mempool: avoid KASAN marking mempool poison checks as use-after-free Date: Fri, 11 Aug 2017 15:02:27 -0700 Message-Id: <20170811220219.982385015@linuxfoundation.org> X-Mailer: git-send-email 2.14.0 In-Reply-To: <20170811220219.438083791@linuxfoundation.org> References: <20170811220219.438083791@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1153 Lines: 37 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Dawson commit 7640131032db9118a78af715ac77ba2debeeb17c upstream. When removing an element from the mempool, mark it as unpoisoned in KASAN before verifying its contents for SLUB/SLAB debugging. Otherwise KASAN will flag the reads checking the element use-after-free writes as use-after-free reads. Signed-off-by: Matthew Dawson Acked-by: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Andrii Bordunov Signed-off-by: Greg Kroah-Hartman --- mm/mempool.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/mempool.c +++ b/mm/mempool.c @@ -135,8 +135,8 @@ static void *remove_element(mempool_t *p void *element = pool->elements[--pool->curr_nr]; BUG_ON(pool->curr_nr < 0); - check_element(pool, element); kasan_unpoison_element(pool, element); + check_element(pool, element); return element; }