From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752072Ab3FDWlE (ORCPT ); Tue, 4 Jun 2013 18:41:04 -0400 Received: from 1wt.eu ([62.212.114.60]:35135 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751728Ab3FDWkl (ORCPT ); Tue, 4 Jun 2013 18:40:41 -0400 Message-Id: <20130604172131.553536735@1wt.eu> User-Agent: quilt/0.48-1 Date: Tue, 04 Jun 2013 19:22:00 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Bjorn Helgaas , Greg Kroah-Hartman , Willy Tarreau Subject: [ 030/184] Driver core: treat unregistered bus_types as having In-Reply-To: <58df134a4b98edf5b0073e2e1e988fe6@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ no devices From: Bjorn Helgaas commit 4fa3e78be7e985ca814ce2aa0c09cbee404efcf7 upstream. A bus_type has a list of devices (klist_devices), but the list and the subsys_private structure that contains it are not initialized until the bus_type is registered with bus_register(). The panic/reboot path has fixups that look up devices in pci_bus_type. If we panic before registering pci_bus_type, the bus_type exists but the list does not, so mach_reboot_fixups() trips over a null pointer and panics again: mach_reboot_fixups pci_get_device .. bus_find_device(&pci_bus_type, ...) bus->p is NULL Joonsoo reported a problem when panicking before PCI was initialized. I think this patch should be sufficient to replace the patch he posted here: https://lkml.org/lkml/2012/12/28/75 ("[PATCH] x86, reboot: skip reboot_fixups in early boot phase") Reported-by: Joonsoo Kim Signed-off-by: Bjorn Helgaas Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- drivers/base/bus.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 63c143e..6f1ba10 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -289,7 +289,7 @@ int bus_for_each_dev(struct bus_type *bus, struct device *start, struct device *dev; int error = 0; - if (!bus) + if (!bus || !bus->p) return -EINVAL; klist_iter_init_node(&bus->p->klist_devices, &i, @@ -323,7 +323,7 @@ struct device *bus_find_device(struct bus_type *bus, struct klist_iter i; struct device *dev; - if (!bus) + if (!bus || !bus->p) return NULL; klist_iter_init_node(&bus->p->klist_devices, &i, -- 1.7.12.2.21.g234cd45.dirty