From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:39350 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753223AbcKGQ0O (ORCPT ); Mon, 7 Nov 2016 11:26:14 -0500 Subject: Patch "mm/list_lru.c: avoid error-path NULL pointer deref" has been added to the 4.8-stable tree To: apolyakov@beget.ru, akpm@linux-foundation.org, gregkh@linuxfoundation.org, torvalds@linux-foundation.org, vdavydov.dev@gmail.com, viro@zeniv.linux.org.uk Cc: , From: Date: Mon, 07 Nov 2016 17:24:20 +0100 Message-ID: <1478535860252108@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled mm/list_lru.c: avoid error-path NULL pointer deref to the 4.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-list_lru.c-avoid-error-path-null-pointer-deref.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 1bc11d70b5db7c6bb1414b283d7f09b1fe1ac0d0 Mon Sep 17 00:00:00 2001 From: Alexander Polakov Date: Thu, 27 Oct 2016 17:46:27 -0700 Subject: mm/list_lru.c: avoid error-path NULL pointer deref From: Alexander Polakov commit 1bc11d70b5db7c6bb1414b283d7f09b1fe1ac0d0 upstream. As described in https://bugzilla.kernel.org/show_bug.cgi?id=177821: After some analysis it seems to be that the problem is in alloc_super(). In case list_lru_init_memcg() fails it goes into destroy_super(), which calls list_lru_destroy(). And in list_lru_init() we see that in case memcg_init_list_lru() fails, lru->node is freed, but not set NULL, which then leads list_lru_destroy() to believe it is initialized and call memcg_destroy_list_lru(). memcg_destroy_list_lru() in turn can access lru->node[i].memcg_lrus, which is NULL. [akpm@linux-foundation.org: add comment] Signed-off-by: Alexander Polakov Acked-by: Vladimir Davydov Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/list_lru.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -554,6 +554,8 @@ int __list_lru_init(struct list_lru *lru err = memcg_init_list_lru(lru, memcg_aware); if (err) { kfree(lru->node); + /* Do this so a list_lru_destroy() doesn't crash: */ + lru->node = NULL; goto out; } Patches currently in stable-queue which might be from apolyakov@beget.ru are queue-4.8/mm-list_lru.c-avoid-error-path-null-pointer-deref.patch