Re: [PATCH v2] edac_mc: Cleanup per-dimm_info debug messages

[Joe Perches]

On Mon, 2012-04-30 at 12:02 -0300, Mauro Carvalho Chehab wrote:
> The edac_mc_alloc() routine allocates one dimm_info device for all
> possible memories, including the non-filled ones. The debug messages
> there are somewhat confusing. So, cleans them, by moving the code
> that prints the memory location to edac_mc, and using it on both
> edac_mc_sysfs and edac_mc.
[]
> diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
[]
> @@ -40,6 +40,25 @@
>  static DEFINE_MUTEX(mem_ctls_mutex);
>  static LIST_HEAD(mc_devices);
>  
> +unsigned edac_dimm_info_location(struct dimm_info *dimm, char *buf,
> +			         int len)
> +{
> +	struct mem_ctl_info *mci = dimm->mci;
> +	int i, n, count = 0;
> +	char *p = buf;
> +
> +	for (i = 0; i < mci->n_layers; i++) {
> +		n = snprintf(p, len, "%s %d ",
> +			      edac_layer_name[mci->layers[i].type],
> +			      dimm->location[i]);
> +		p += n;
> +		len -= n;
> +		count += n;
> +	}

I believe this snprintf can be unsafe
when the buffer length len is exceeded.

if len is negative, it's promoted to size_t
and continues to write into p.


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