From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e24smtp05.br.ibm.com (e24smtp05.br.ibm.com [32.104.18.26]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e24smtp05.br.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id BBF10B7D42 for ; Wed, 3 Feb 2010 04:46:35 +1100 (EST) Received: from mailhub1.br.ibm.com (mailhub1.br.ibm.com [9.18.232.109]) by e24smtp05.br.ibm.com (8.14.3/8.13.1) with ESMTP id o12HZNr1007829 for ; Tue, 2 Feb 2010 15:35:23 -0200 Received: from d24av05.br.ibm.com (d24av05.br.ibm.com [9.18.232.44]) by mailhub1.br.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o12Hmwd4446852 for ; Tue, 2 Feb 2010 15:48:58 -0200 Received: from d24av05.br.ibm.com (loopback [127.0.0.1]) by d24av05.br.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o12HkSB0016047 for ; Tue, 2 Feb 2010 15:46:29 -0200 Message-ID: <4B6864F4.1030106@linux.vnet.ibm.com> Date: Tue, 02 Feb 2010 15:46:28 -0200 From: Breno Leitao MIME-Version: 1.0 To: benh@kernel.crashing.org, linuxppc-dev@ozlabs.org Subject: [PATCH] eeh: Fixing a bug when pci structure is null References: <1264789719-15591-1-git-send-email-leitao@linux.vnet.ibm.com> In-Reply-To: <1264789719-15591-1-git-send-email-leitao@linux.vnet.ibm.com> Content-Type: text/plain; charset=UTF-8 Cc: Linas Vepstas List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , During a EEH recover, the pci_dev structure can be null, mainly if an eeh event is detected during cpi config operation. In this case, the pci_dev will not be known (and will be null) and the kernel will crash with the following message: Unable to handle kernel paging request for data at address 0x000000a0 Faulting instruction address: 0xc00000000006b8b4 Oops: Kernel access of bad area, sig: 11 [#1] NIP [c00000000006b8b4] .eeh_event_handler+0x10c/0x1a0 LR [c00000000006b8a8] .eeh_event_handler+0x100/0x1a0 Call Trace: [c0000003a80dff00] [c00000000006b8a8] .eeh_event_handler+0x100/0x1a0 [c0000003a80dff90] [c000000000031f1c] .kernel_thread+0x54/0x70 The bug occurs because pci_name() tries to access a null pointer. This patch just guarantee that pci_name() is not called on Null pointers. Signed-off-by: Breno Leitao Signed-off-by: Linas Vepstas --- arch/powerpc/include/asm/ppc-pci.h | 7 +++++++ arch/powerpc/platforms/pseries/eeh.c | 4 ++-- arch/powerpc/platforms/pseries/eeh_driver.c | 4 ++-- arch/powerpc/platforms/pseries/eeh_event.c | 2 +- 4 files changed, 12 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/ppc-pci.h b/arch/powerpc/include/asm/ppc-pci.h index 2828f9d..724dbe2 100644 --- a/arch/powerpc/include/asm/ppc-pci.h +++ b/arch/powerpc/include/asm/ppc-pci.h @@ -137,6 +137,13 @@ struct device_node * find_device_pe(struct device_node *dn); void eeh_sysfs_add_device(struct pci_dev *pdev); void eeh_sysfs_remove_device(struct pci_dev *pdev); +static inline const char *eeh_pci_name(struct pci_dev *pdev) +{ + if (NULL==pdev) + return ""; + return pci_name(pdev); +} + #endif /* CONFIG_EEH */ #else /* CONFIG_PCI */ diff --git a/arch/powerpc/platforms/pseries/eeh.c b/arch/powerpc/platforms/pseries/eeh.c index ccd8dd0..f9360fe 100644 --- a/arch/powerpc/platforms/pseries/eeh.c +++ b/arch/powerpc/platforms/pseries/eeh.c @@ -491,7 +491,7 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev) pdn->eeh_mode & EEH_MODE_NOCHECK) { ignored_check++; pr_debug("EEH: Ignored check (%x) for %s %s\n", - pdn->eeh_mode, pci_name (dev), dn->full_name); + pdn->eeh_mode, eeh_pci_name (dev), dn->full_name); return 0; } @@ -515,7 +515,7 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev) printk (KERN_ERR "EEH: %d reads ignored for recovering device at " "location=%s driver=%s pci addr=%s\n", pdn->eeh_check_count, location, - dev->driver->name, pci_name(dev)); + dev->driver->name, eeh_pci_name(dev)); printk (KERN_ERR "EEH: Might be infinite loop in %s driver\n", dev->driver->name); dump_stack(); diff --git a/arch/powerpc/platforms/pseries/eeh_driver.c b/arch/powerpc/platforms/pseries/eeh_driver.c index ef8e454..8f948a0 100644 --- a/arch/powerpc/platforms/pseries/eeh_driver.c +++ b/arch/powerpc/platforms/pseries/eeh_driver.c @@ -337,7 +337,7 @@ struct pci_dn * handle_eeh_events (struct eeh_event *event) location = location ? location : "unknown"; printk(KERN_ERR "EEH: Error: Cannot find partition endpoint " "for location=%s pci addr=%s\n", - location, pci_name(event->dev)); + location, eeh_pci_name(event->dev)); return NULL; } @@ -368,7 +368,7 @@ struct pci_dn * handle_eeh_events (struct eeh_event *event) pci_str = pci_name (frozen_pdn->pcidev); drv_str = pcid_name (frozen_pdn->pcidev); } else { - pci_str = pci_name (event->dev); + pci_str = eeh_pci_name (event->dev); drv_str = pcid_name (event->dev); } diff --git a/arch/powerpc/platforms/pseries/eeh_event.c b/arch/powerpc/platforms/pseries/eeh_event.c index ddb80f5..ec5df8f 100644 --- a/arch/powerpc/platforms/pseries/eeh_event.c +++ b/arch/powerpc/platforms/pseries/eeh_event.c @@ -80,7 +80,7 @@ static int eeh_event_handler(void * dummy) eeh_mark_slot(event->dn, EEH_MODE_RECOVERING); printk(KERN_INFO "EEH: Detected PCI bus error on device %s\n", - pci_name(event->dev)); + eeh_pci_name(event->dev)); pdn = handle_eeh_events(event);