From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751503AbaIUPv7 (ORCPT ); Sun, 21 Sep 2014 11:51:59 -0400 Received: from mail-pd0-f175.google.com ([209.85.192.175]:45904 "EHLO mail-pd0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751297AbaIUPv5 (ORCPT ); Sun, 21 Sep 2014 11:51:57 -0400 From: Guenter Roeck To: Andrew Morton Cc: Mikael Starvik , Jesper Nilsson , linux-kernel@vger.kernel.org, Guenter Roeck , Vivek Goyal Subject: [PATCH] resource: Add NULL check in next_resource Date: Sun, 21 Sep 2014 08:51:44 -0700 Message-Id: <1411314704-27072-1-git-send-email-linux@roeck-us.net> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 8c86e70acead ("resource: provide new functions to walk through resources") adds a suble new requirement that iomem_resource.child must not be NULL when walk_system_ram_range is called. This can cause a crash if it turns out that there are no children. The crash ('Unable to handle kernel NULL pointer dereference') is seen when trying to test a crisv32 image on kernels with this commit applied. Fix by adding a NULL check into next_resource(). Fixes: 8c86e70acead ("resource: provide new functions to walk through resources") Cc: Vivek Goyal Cc: Andrew Morton Signed-off-by: Guenter Roeck --- The NULL check could be added elsewhere instead. I am open to suggestions. kernel/resource.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/resource.c b/kernel/resource.c index 60c5a38..00c57ad 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -61,6 +61,9 @@ static DEFINE_SPINLOCK(bootmem_resource_lock); static struct resource *next_resource(struct resource *p, bool sibling_only) { + if (p == NULL) + return NULL; + /* Caller wants to traverse through siblings only */ if (sibling_only) return p->sibling; -- 1.9.1