From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757372AbYDGXnK (ORCPT ); Mon, 7 Apr 2008 19:43:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752614AbYDGXm5 (ORCPT ); Mon, 7 Apr 2008 19:42:57 -0400 Received: from g5t0006.atlanta.hp.com ([15.192.0.43]:5310 "EHLO g5t0006.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752113AbYDGXm4 (ORCPT ); Mon, 7 Apr 2008 19:42:56 -0400 Date: Mon, 7 Apr 2008 17:42:55 -0600 From: Alex Chiang To: Badari Pulavarty Cc: Andrew Morton , lkml , linas@austin.ibm.com Subject: Re: 2.6.25-rc8-mm1 panic in rpaphp_register_slot() Message-ID: <20080407234255.GA22514@ldl.fc.hp.com> Mail-Followup-To: Alex Chiang , Badari Pulavarty , Andrew Morton , lkml , linas@austin.ibm.com References: <1207331616.5916.15.camel@badari-desktop> <20080404180518.GA12642@ldl.fc.hp.com> <1207340371.5916.23.camel@badari-desktop> <20080404224227.GA31436@ldl.fc.hp.com> <1207352128.5916.26.camel@badari-desktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1207352128.5916.26.camel@badari-desktop> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Badari, > > > pci_hotplug: PCI Hot Plug PCI Core version: 0.5 > > > rpaphp: RPA HOT Plug PCI Controller Driver version: 0.1 > > > rpaphp_register_slot registering slot:path[/pci@800000020000003/pci@2,4] index[22010003], name[U787E.001.AAA3015-P2-C1] pdomain[22010003] type[16] > > > Unable to handle kernel paging request for data at address 0x00000070 > > > > Hrm, this is a little more information, but still not quite > > enough. I'm going to take a stab in the dark and say I'm probably > > doing something wrong on this line, maybe dereferencing a pointer > > incorrectly: > > > > retval = pci_hp_register(php_slot, slot->bus, > > PCI_SLOT(PCI_DN(slot->dn->child)->devfn)); > > Sorry. I thought you knew this already. Disassembly clearly showed > that slot->dn->child is NULL. > > I confirmed it by adding printk also. This patch is a complete guess on my part (since I've not been able to understand pseries architecture) but I think it should fix your issue. Can you give it a try and let me know? It applies on top of the -mm tree that includes my physical pci_slot series. Also, I'm hoping Linas will speak up and let me know what the real answer might be. ;) Thanks. /ac From: Alex Chiang Subject: rpaphp: correctly call pci_hp_register for empty PCI slots Unpopulated device_node slots do not have children, and attempting to dereference them will result in a panic. Instead, attempt to derive the PCI slot number from the bus itself, and failing that, default to 0. Signed-off-by: Alex Chiang --- diff --git a/drivers/pci/hotplug/rpaphp_slot.c b/drivers/pci/hotplug/rpaphp_slot.c index 0d4cfc7..91ce6a6 100644 --- a/drivers/pci/hotplug/rpaphp_slot.c +++ b/drivers/pci/hotplug/rpaphp_slot.c @@ -121,6 +121,7 @@ int rpaphp_register_slot(struct slot *slot) { struct hotplug_slot *php_slot = slot->hotplug_slot; int retval; + int slot_nr; dbg("%s registering slot:path[%s] index[%x], name[%s] pdomain[%x] type[%d]\n", __FUNCTION__, slot->dn->full_name, slot->index, slot->name, @@ -132,8 +133,11 @@ int rpaphp_register_slot(struct slot *slot) return -EAGAIN; } - retval = pci_hp_register(php_slot, slot->bus, - PCI_SLOT(PCI_DN(slot->dn->child)->devfn)); + if (slot->bus->self) + slot_nr = PCI_SLOT(slot->bus->self->devfn); + else + slot_nr = 0; + retval = pci_hp_register(php_slot, slot->bus, slot_nr); if (retval) { err("pci_hp_register failed with error %d\n", retval); return retval;