From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934384AbaFIWqa (ORCPT ); Mon, 9 Jun 2014 18:46:30 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57010 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933964AbaFIWpv (ORCPT ); Mon, 9 Jun 2014 18:45:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrey Ryabinin , Peter Zijlstra , Linus Torvalds Subject: [PATCH 3.14 69/78] mm: rmap: fix use-after-free in __put_anon_vma Date: Mon, 9 Jun 2014 15:48:49 -0700 Message-Id: <20140609224815.548589111@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140609224813.282275135@linuxfoundation.org> References: <20140609224813.282275135@linuxfoundation.org> User-Agent: quilt/0.63-1 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 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrey Ryabinin commit 624483f3ea82598ab0f62f1bdb9177f531ab1892 upstream. While working address sanitizer for kernel I've discovered use-after-free bug in __put_anon_vma. For the last anon_vma, anon_vma->root freed before child anon_vma. Later in anon_vma_free(anon_vma) we are referencing to already freed anon_vma->root to check rwsem. This fixes it by freeing the child anon_vma before freeing anon_vma->root. Signed-off-by: Andrey Ryabinin Acked-by: Peter Zijlstra Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/rmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1554,10 +1554,9 @@ void __put_anon_vma(struct anon_vma *ano { struct anon_vma *root = anon_vma->root; + anon_vma_free(anon_vma); if (root != anon_vma && atomic_dec_and_test(&root->refcount)) anon_vma_free(root); - - anon_vma_free(anon_vma); } static struct anon_vma *rmap_walk_anon_lock(struct page *page,