Subject: Re: [PATCH 3/5] powerpc/perf: fix imc allocation failure handling

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Wed, 24 Jul 2019 15:28:02 +0530

Nicholas Piggin <[email-masked]> writes:

> The alloc_pages_node return value should be tested for failure
> before being passed to page_address.
>

Reviewed-by: Aneesh Kumar K.V <[email-masked]>

This need Fixes: tag? It fix a real crash unlike the other patch in this
series? 

> Cc: Madhavan Srinivasan <[email-masked]>
> Tested-by: Anju T Sudhakar <[email-masked]>
> Signed-off-by: Nicholas Piggin <[email-masked]>
> ---
>  arch/powerpc/perf/imc-pmu.c | 29 ++++++++++++++++++-----------
>  1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
> index dea243185ea4..cb50a9e1fd2d 100644
> --- a/arch/powerpc/perf/imc-pmu.c
> +++ b/arch/powerpc/perf/imc-pmu.c
> @@ -577,6 +577,7 @@ static int core_imc_mem_init(int cpu, int size)
>  {
>  	int nid, rc = 0, core_id = (cpu / threads_per_core);
>  	struct imc_mem_info *mem_info;
> +	struct page *page;
>  
>  	/*
>  	 * alloc_pages_node() will allocate memory for core in the
> @@ -587,11 +588,12 @@ static int core_imc_mem_init(int cpu, int size)
>  	mem_info->id = core_id;
>  
>  	/* We need only vbase for core counters */
> -	mem_info->vbase = page_address(alloc_pages_node(nid,
> -					  GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE |
> -					  __GFP_NOWARN, get_order(size)));
> -	if (!mem_info->vbase)
> +	page = alloc_pages_node(nid,
> +				GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE |
> +				__GFP_NOWARN, get_order(size));
> +	if (!page)
>  		return -ENOMEM;
> +	mem_info->vbase = page_address(page);
>  
>  	/* Init the mutex */
>  	core_imc_refc[core_id].id = core_id;
> @@ -849,15 +851,17 @@ static int thread_imc_mem_alloc(int cpu_id, int size)
>  	int nid = cpu_to_node(cpu_id);
>  
>  	if (!local_mem) {
> +		struct page *page;
>  		/*
>  		 * This case could happen only once at start, since we dont
>  		 * free the memory in cpu offline path.
>  		 */
> -		local_mem = page_address(alloc_pages_node(nid,
> +		page = alloc_pages_node(nid,
>  				  GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE |
> -				  __GFP_NOWARN, get_order(size)));
> -		if (!local_mem)
> +				  __GFP_NOWARN, get_order(size));
> +		if (!page)
>  			return -ENOMEM;
> +		local_mem = page_address(page);
>  
>  		per_cpu(thread_imc_mem, cpu_id) = local_mem;
>  	}
> @@ -1095,11 +1099,14 @@ static int trace_imc_mem_alloc(int cpu_id, int size)
>  	int core_id = (cpu_id / threads_per_core);
>  
>  	if (!local_mem) {
> -		local_mem = page_address(alloc_pages_node(phys_id,
> -					GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE |
> -					__GFP_NOWARN, get_order(size)));
> -		if (!local_mem)
> +		struct page *page;
> +
> +		page = alloc_pages_node(phys_id,
> +				GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE |
> +				__GFP_NOWARN, get_order(size));
> +		if (!page)
>  			return -ENOMEM;
> +		local_mem = page_address(page);
>  		per_cpu(trace_imc_mem, cpu_id) = local_mem;
>  
>  		/* Initialise the counters for trace mode */
> -- 
> 2.22.0