Re: [113/197] x86, cacheinfo: Calculate L3 indices

[Borislav Petkov]

From: Jiri Kosina <jkosina@xxxxxxx>
Date: Wed, May 05, 2010 at 12:26:19PM -0400

> Please consider applying the patch below, both for 2.6.34 and all the 
> -stable kernels this patch has hit.
> 
> 
> 
> From: Jiri Kosina <jkosina@xxxxxxx>
> Subject: [PATCH] x86, cacheinfo: fix oops in amd_calc_l3_indices()
> 
> Commit 048a8774ca4348 ("x86, cacheinfo: Calculate L3 indices") introduced
> amd_calc_l3_indices(), but this function doesn't properly handle case
> when node_to_k8_nb_misc() returns NULL, causing immediate oops due to
> NULL pointer dereference in pci_read_config_dword().
> 
> Make amd_calc_l3_indices() return -1 in such cases. This is correct
> lower bound, as it will make store_cache_disable() return EINVAL in
> all such cases.
> 
> Cc: stable@xxxxxxxxxx
> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
> ---
>  arch/x86/kernel/cpu/intel_cacheinfo.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
> index b3eeb66..b9f8dca 100644
> --- a/arch/x86/kernel/cpu/intel_cacheinfo.c
> +++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
> @@ -314,6 +314,9 @@ static unsigned int __cpuinit amd_calc_l3_indices(void)
>  	unsigned int sc0, sc1, sc2, sc3;
>  	u32 val = 0;
>  
> +	if (!dev)
> +		return -1;
> +

This won't fly since the function returns an unsigned value and the L3
code would still be entered, which is what you don't want actually when
k8_northbridges initialization has somehow failed.

Rather, we have a fix already which should take care of your issue too,
see http://git.kernel.org/tip/f2b20e41407fccfcfacf927ff91ec888832a37af

I was waiting for it to hit mainline before I backport it to stable and
it would be helpful if you could verify that it works for you along with
0e152cd7c16832bd5cadee0c2e41d9959bc9b6f9 you sent earlier.

Thanks.

-- 
Regards/Gruss,
Boris.

--
Advanced Micro Devices, Inc.
Operating Systems Research Center

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/