Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932698AbVJCVtn (ORCPT ); Mon, 3 Oct 2005 17:49:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932702AbVJCVtn (ORCPT ); Mon, 3 Oct 2005 17:49:43 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:62693 "EHLO e2.ny.us.ibm.com") by vger.kernel.org with ESMTP id S932698AbVJCVtm (ORCPT ); Mon, 3 Oct 2005 17:49:42 -0400 Date: Mon, 3 Oct 2005 16:49:40 -0500 To: Alexey Dobriyan Cc: paulus@samba.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org, johnrose@austin.ibm.com Subject: Re: [PATCH] ppc64: Crash in DLPAR code on PCI hotplug add Message-ID: <20051003214940.GT29826@austin.ibm.com> References: <20051003185739.GR29826@austin.ibm.com> <20051003213430.GD7554@mipter.zuzino.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051003213430.GD7554@mipter.zuzino.mipt.ru> User-Agent: Mutt/1.5.6+20040907i From: linas Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2993 Lines: 81 On Tue, Oct 04, 2005 at 01:34:30AM +0400, Alexey Dobriyan was heard to remark: > > Please, add docs in a proper way: Done, new patch attached. --linas 08-hotplug-bugfix.patch In the current 2.6.14-rc2-git6 kernel, performing a Dynamic LPAR Add of a hotplug slot will crash the system, with the following (abbreviated) stack trace: cpu 0x3: Vector: 700 (Program Check) at [c000000053dff7f0] pc: c0000000004f5974: .__alloc_bootmem+0x0/0xb0 lr: c0000000000258a0: .update_dn_pci_info+0x108/0x118 c0000000000257c8 .update_dn_pci_info+0x30/0x118 (unreliable) c0000000000258fc .pci_dn_reconfig_notifier+0x4c/0x64 c000000000060754 .notifier_call_chain+0x68/0x9c The root cause was that the phb was not marked "dynamic", and so instead of having kmalloc() being called, the __init __alloc_bootmem() was called, resulting in access of garage data. The patch below fixes this crash, and adds some docs to clarify the code. Signed-off-by: Linas Vepstas Index: linux-2.6.14-rc2-git6/arch/ppc64/kernel/pci_dn.c =================================================================== --- linux-2.6.14-rc2-git6.orig/arch/ppc64/kernel/pci_dn.c 2005-10-03 13:45:58.000000000 -0500 +++ linux-2.6.14-rc2-git6/arch/ppc64/kernel/pci_dn.c 2005-10-03 16:46:33.816658976 -0500 @@ -121,6 +121,14 @@ return NULL; } +/** + * pci_devs_phb_init_dynamic - setup pci devices under this PHB + * phb: pci-to-host bridge (top-level bridge connecting to cpu) + * + * This routine is called both during boot, (before the memory + * subsystem is set up, before kmalloc is valid) and during the + * dynamic lpar operation of adding a PHB to a running system. + */ void __devinit pci_devs_phb_init_dynamic(struct pci_controller *phb) { struct device_node * dn = (struct device_node *) phb->arch_data; @@ -201,17 +209,24 @@ .notifier_call = pci_dn_reconfig_notifier, }; -/* - * Actually initialize the phbs. - * The buswalk on this phb has not happened yet. +/** + * pci_devs_phb_init - Initialize phbs and pci devs under them. + * + * This routine walks over all phb's (pci-host bridges) on the + * system, and sets up assorted pci-related structures + * (including pci info in the device node structs) for each + * pci device found underneath. This routine runs once, + * early in the boot sequence. */ void __init pci_devs_phb_init(void) { struct pci_controller *phb, *tmp; /* This must be done first so the device nodes have valid pci info! */ - list_for_each_entry_safe(phb, tmp, &hose_list, list_node) + list_for_each_entry_safe(phb, tmp, &hose_list, list_node) { pci_devs_phb_init_dynamic(phb); + phb->is_dynamic = 1; + } pSeries_reconfig_notifier_register(&pci_dn_reconfig_nb); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/