Re: [ndctl PATCH 3/5] ndctl/dimm: do not increment a ULLONG_MAX slot value

[Dave Jiang <dave.jiang@intel.com>]

On 3/3/25 5:37 PM, alison.schofield@intel.com wrote:
> From: Alison Schofield <alison.schofield@intel.com>
> 
> A coverity scan higlighted an overflow issue when the slot variable,
> an unsigned integer that is initialized to -1, is incremented and
> overflows.
> 
> Initialize slot to 0 and move the increment statement to after slot
> is evaluated. That keeps the comparison to a u32 as is and avoids
> overflow.
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> ---
>  ndctl/dimm.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/ndctl/dimm.c b/ndctl/dimm.c
> index 889b620355fc..c39c69bfa336 100644
> --- a/ndctl/dimm.c
> +++ b/ndctl/dimm.c
> @@ -97,7 +97,7 @@ static struct json_object *dump_label_json(struct ndctl_dimm *dimm,
>  	struct json_object *jlabel = NULL;
>  	struct namespace_label nslabel;
>  	unsigned int nsindex_size;
> -	unsigned int slot = -1;
> +	unsigned int slot = 0;
>  	ssize_t offset;
>  
>  	if (!jarray)
> @@ -115,7 +115,6 @@ static struct json_object *dump_label_json(struct ndctl_dimm *dimm,
>  		struct json_object *jobj;
>  		char uuid[40];
>  
> -		slot++;
>  		jlabel = json_object_new_object();
>  		if (!jlabel)
>  			break;
> @@ -127,8 +126,11 @@ static struct json_object *dump_label_json(struct ndctl_dimm *dimm,
>  		if (len < 0)
>  			break;
>  
> -		if (le32_to_cpu(nslabel.slot) != slot)
> +		if (le32_to_cpu(nslabel.slot) != slot) {
> +			slot++;
>  			continue;
> +		}
> +		slot++;

Wonder if you can just increment the slot in the for() since it's not being used after this. 

>  
>  		uuid_unparse((void *) nslabel.uuid, uuid);
>  		jobj = json_object_new_string(uuid);