[PATCH] eeh: Fixing a bug when pci structure is null

[PATCH] eeh: Fixing a bug when pci structure is null

[Breno Leitao]

 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 <leitao@linux.vnet.ibm.com>
 Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
 ---
  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 "<null>"; 
 +	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);

Re: [PATCH] eeh: Fixing a bug when pci structure is null

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 5051 bytes --]

On Tue, Feb 02, 2010 at 03:46:28PM -0200, Breno Leitao wrote:
>  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 <leitao@linux.vnet.ibm.com>
>  Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
>  ---
>   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 "<null>"; 
>  +	return pci_name(pdev); 

What about:

	return pdev ? pci_name(pdev) : "<null>";


>  +} 
>  +
>   #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);

No space after function name, please.

>   		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));

ditto

>   			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);

ditto

>   		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);
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 197 bytes --]

[PATCH] eeh: Fixing a bug when pci structure is null

[Breno Leitao]

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) 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 <leitao@linux.vnet.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
---
 arch/powerpc/include/asm/ppc-pci.h          |    5 +++++
 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, 10 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/ppc-pci.h b/arch/powerpc/include/asm/ppc-pci.h
index 2828f9d..42fdff0 100644
--- a/arch/powerpc/include/asm/ppc-pci.h
+++ b/arch/powerpc/include/asm/ppc-pci.h
@@ -137,6 +137,11 @@ 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) 
+{ 
+	return pdev ? pci_name(pdev) : "<null>";
+} 
+
 #endif /* CONFIG_EEH */
 
 #else /* CONFIG_PCI */
diff --git a/arch/powerpc/platforms/pseries/eeh.c b/arch/powerpc/platforms/pseries/eeh.c
index ccd8dd0..3304f32 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..977d87d 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);
 
-- 
1.6.0.2

Re: [PATCH] eeh: Fixing a bug when pci structure is null

[Breno Leitao]

Hi Ben, 

I'd like to ask about this patch ? Should I re-submit ?

Thanks, 

Breno Leitao wrote:
> 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) the kernel will crash
> with the following message:

Re: [PATCH] eeh: Fixing a bug when pci structure is null

[Linas Vepstas]

Hi Paul, Breno,

Some confusion -- I've been out of the loop for a while -- I assume
its still Paul who is pushing
these patches upstream, and not Ben?  So Breno, maybe you should
resend the patch to Paul?

--linas

On 19 February 2010 10:43, Breno Leitao <leitao@linux.vnet.ibm.com> wrote:
> Hi Ben,
>
> I'd like to ask about this patch ? Should I re-submit ?
>
> Thanks,
>
> Breno Leitao wrote:
>> 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) the kernel will crash
>> with the following message:
>

Re: [PATCH] eeh: Fixing a bug when pci structure is null

[Benjamin Herrenschmidt]

On Fri, 2010-02-19 at 14:43 -0200, Breno Leitao wrote:
> Hi Ben, 
> 
> I'd like to ask about this patch ? Should I re-submit ?
> 
> Thanks, 
> 
> Breno Leitao wrote:
> > 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) the kernel will crash
> > with the following message:

It should be in -next, can you dbl check ?

Cheers,
Ben.

Re: [PATCH] eeh: Fixing a bug when pci structure is null

[Benjamin Herrenschmidt]

On Fri, 2010-02-19 at 11:05 -0600, Linas Vepstas wrote:
> 
> Some confusion -- I've been out of the loop for a while -- I assume
> its still Paul who is pushing
> these patches upstream, and not Ben?  So Breno, maybe you should
> resend the patch to Paul? 

No, it's me.

Cheers,
Ben.

Re: [PATCH] eeh: Fixing a bug when pci structure is null

[Mike Mason]

On 2/19/2010 1:54 PM, Benjamin Herrenschmidt wrote:
> On Fri, 2010-02-19 at 14:43 -0200, Breno Leitao wrote:
>> Hi Ben,
>>
>> I'd like to ask about this patch ? Should I re-submit ?
>>
>> Thanks,
>>
>> Breno Leitao wrote:
>>> 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) the kernel will crash
>>> with the following message:
>
> It should be in -next, can you dbl check ?

I just confirmed the patch is in the -next tree.

Mike

>
> Cheers,
> Ben.
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev