[PATCH] powerpc/book3s: Fix MCE console messages for unrecoverable MCE.

[PATCH] powerpc/book3s: Fix MCE console messages for unrecoverable MCE.

[Mahesh J Salgaonkar]

From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>

When machine check occurs with MSR(RI=0), it means MC interrupt is
unrecoverable and kernel goes down to panic path. But the console
message still shows it as recovered. This patch fixes the MCE console
messages.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/mce.c             |    3 ++-
 arch/powerpc/platforms/powernv/opal.c |    2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index ef267fd..5e7ece0 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -92,7 +92,8 @@ void save_mce_event(struct pt_regs *regs, long handled,
 	mce->in_use = 1;
 
 	mce->initiator = MCE_INITIATOR_CPU;
-	if (handled)
+	/* Mark it recovered if we have handled it and MSR(RI=1). */
+	if (handled && (regs->msr & MSR_RI))
 		mce->disposition = MCE_DISPOSITION_RECOVERED;
 	else
 		mce->disposition = MCE_DISPOSITION_NOT_RECOVERED;
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 5385434..8154171 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -401,6 +401,8 @@ static int opal_recover_mce(struct pt_regs *regs,
 
 	if (!(regs->msr & MSR_RI)) {
 		/* If MSR_RI isn't set, we cannot recover */
+		printk(KERN_ERR "Machine check interrupt unrecoverable:"
+				" MSR(RI=0)\n");
 		recovered = 0;
 	} else if (evt->disposition == MCE_DISPOSITION_RECOVERED) {
 		/* Platform corrected itself */

Re: [PATCH] powerpc/book3s: Fix MCE console messages for unrecoverable MCE.

[Greg KH]

On Thu, Aug 04, 2016 at 10:16:48AM +0530, Mahesh J Salgaonkar wrote:
> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> 
> When machine check occurs with MSR(RI=0), it means MC interrupt is
> unrecoverable and kernel goes down to panic path. But the console
> message still shows it as recovered. This patch fixes the MCE console
> messages.
> 
> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> ---
>  arch/powerpc/kernel/mce.c             |    3 ++-
>  arch/powerpc/platforms/powernv/opal.c |    2 ++
>  2 files changed, 4 insertions(+), 1 deletion(-)


<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>

Re: [PATCH] powerpc/book3s: Fix MCE console messages for unrecoverable MCE.

[Mahesh Jagannath Salgaonkar]

On 08/04/2016 01:35 PM, Greg KH wrote:
> On Thu, Aug 04, 2016 at 10:16:48AM +0530, Mahesh J Salgaonkar wrote:
>> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
>>
>> When machine check occurs with MSR(RI=0), it means MC interrupt is
>> unrecoverable and kernel goes down to panic path. But the console
>> message still shows it as recovered. This patch fixes the MCE console
>> messages.
>>
>> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
>> ---
>>  arch/powerpc/kernel/mce.c             |    3 ++-
>>  arch/powerpc/platforms/powernv/opal.c |    2 ++
>>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> 
> <formletter>
> 
> This is not the correct way to submit patches for inclusion in the
> stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
> for how to do this properly.
> 
> </formletter>
> 

Ouch. My mistake. Will follow Documentation/stable_kernel_rules.txt

Thanks,
-Mahesh.

Re: [PATCH] powerpc/book3s: Fix MCE console messages for unrecoverable MCE.

[Michael Ellerman]

Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com> writes:

> On 08/04/2016 01:35 PM, Greg KH wrote:
>> On Thu, Aug 04, 2016 at 10:16:48AM +0530, Mahesh J Salgaonkar wrote:
>>> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
>>>
>>> When machine check occurs with MSR(RI=0), it means MC interrupt is
>>> unrecoverable and kernel goes down to panic path. But the console
>>> message still shows it as recovered. This patch fixes the MCE console
>>> messages.
>>>
>>> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
>> 
>> <formletter>
>> 
>> This is not the correct way to submit patches for inclusion in the
>> stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
>> for how to do this properly.
>> 
>> </formletter>
>
> Ouch. My mistake. Will follow Documentation/stable_kernel_rules.txt

Additionally I appreciate it if you can add a Fixes: line. Which
indicates the commit that introduced the bug you are fixing. It is
documented in Documentation/SubmittingPatches.

In this case it looks like it would be:

Fixes: 36df96f8acaf ("powerpc/book3s: Decode and save machine check event.")

cheers