From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757297Ab2BAVNP (ORCPT ); Wed, 1 Feb 2012 16:13:15 -0500 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:46740 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932657Ab2BAVKn (ORCPT ); Wed, 1 Feb 2012 16:10:43 -0500 X-Sasl-enc: 7r8AaCzknUsYz9Z787g4zfKNUaVSw/HV1j2lXm31yXjA 1328130641 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Feb 1 13:00:50 2012 Message-Id: <20120201210050.032645006@clark.kroah.org> User-Agent: quilt/0.51-15.1 Date: Wed, 01 Feb 2012 13:00:34 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, "Eric W. Biederman" , Sasha Levin , "David S. Miller" Subject: [70/89] netns: Fail conspicously if someone uses net_generic at an inappropriate time. In-Reply-To: <20120201210505.GA26028@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Eric W. Biederman" [ Upstream commit 5ee4433efe99b9f39f6eff5052a177bbcfe72cea ] By definition net_generic should never be called when it can return NULL. Fail conspicously with a BUG_ON to make it clear when people mess up that a NULL return should never happen. Recently there was a bug in the CAIF subsystem where it was registered with register_pernet_device instead of register_pernet_subsys. It was erroneously concluded that net_generic could validly return NULL and that net_assign_generic was buggy (when it was just inefficient). Hopefully this BUG_ON will prevent people to coming to similar erroneous conclusions in the futrue. Signed-off-by: Eric W. Biederman Tested-by: Sasha Levin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/netns/generic.h | 1 + 1 file changed, 1 insertion(+) --- a/include/net/netns/generic.h +++ b/include/net/netns/generic.h @@ -41,6 +41,7 @@ static inline void *net_generic(const st ptr = ng->ptr[id - 1]; rcu_read_unlock(); + BUG_ON(!ptr); return ptr; } #endif