[PATCH 1/8] powerpc/64s/powernv: Fix memory corruption when saving SLB entries on MCE

[Mahesh J Salgaonkar]

On 2020-11-28 17:07:21 Sat, Nicholas Piggin wrote:
> This can be hit by an HPT guest running on an HPT host and bring down
> the host, so it's quite important to fix.
> 
> Fixes: 7290f3b3d3e66 ("powerpc/64s/powernv: machine check dump SLB contents")
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
>  arch/powerpc/platforms/powernv/setup.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
> index 46115231a3b2..4426a109ec2f 100644
> --- a/arch/powerpc/platforms/powernv/setup.c
> +++ b/arch/powerpc/platforms/powernv/setup.c
> @@ -211,11 +211,16 @@ static void __init pnv_init(void)
>  		add_preferred_console("hvc", 0, NULL);
>  
>  	if (!radix_enabled()) {
> +		size_t size = sizeof(struct slb_entry) * mmu_slb_size;

Acked-by: Mahesh Salgaonkar <mahesh at linux.ibm.com>

Thanks,
-Mahesh.


>  		int i;
>  
>  		/* Allocate per cpu area to save old slb contents during MCE */
> -		for_each_possible_cpu(i)
> -			paca_ptrs[i]->mce_faulty_slbs = memblock_alloc_node(mmu_slb_size, __alignof__(*paca_ptrs[i]->mce_faulty_slbs), cpu_to_node(i));
> +		for_each_possible_cpu(i) {
> +			paca_ptrs[i]->mce_faulty_slbs =
> +					memblock_alloc_node(size,
> +						__alignof__(struct slb_entry),
> +						cpu_to_node(i));
> +		}
>  	}
>  }
>  
> -- 
> 2.23.0
> 

-- 
Mahesh J Salgaonkar