From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751676Ab1AXUNw (ORCPT ); Mon, 24 Jan 2011 15:13:52 -0500 Received: from swampdragon.chaosbits.net ([90.184.90.115]:14903 "EHLO swampdragon.chaosbits.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750735Ab1AXUNv (ORCPT ); Mon, 24 Jan 2011 15:13:51 -0500 Date: Mon, 24 Jan 2011 21:14:33 +0100 (CET) From: Jesper Juhl To: linux-pci@vger.kernel.org cc: linux-kernel@vger.kernel.org, Jesse Barnes Subject: [PATCH] PCI: Avoid potential NULL pointer dereference in pci_scan_bridge Message-ID: User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pci_add_new_bus() calls pci_alloc_child_bus() which calls pci_alloc_bus() that allocates memory dynamically with kzalloc(). The return value of kzalloc() is the pointer that's eventually returned from pci_add_new_bus(), so since kzalloc() can fail and return NULL so can pci_add_new_bus(). Thus we may end up dereferencing a NULL pointer in drivers/pci/probe.c::pci_scan_bridge(). Seems to me we should test for this and bail out if it happens rather than crashing. Also removed some trailing whitespace that bugged me while looking at this. Signed-off-by: Jesper Juhl --- probe.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) compile tested diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index c84900d..44cbbba 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -764,6 +764,8 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, if (pci_find_bus(pci_domain_nr(bus), max+1)) goto out; child = pci_add_new_bus(bus, dev, ++max); + if (!child) + goto out; buses = (buses & 0xff000000) | ((unsigned int)(child->primary) << 0) | ((unsigned int)(child->secondary) << 8) @@ -777,7 +779,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, buses &= ~0xff000000; buses |= CARDBUS_LATENCY_TIMER << 24; } - + /* * We need to blast all three values with a single write. */ -- Jesper Juhl http://www.chaosbits.net/ Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please.