powerpc/perf: Fix a sizeof() typo so we allocate less memory

[Michael Ellerman]

Dan Carpenter <dan.carpenter at oracle.com> writes:

> We're allocating the size of the struct which is 32 bytes when we should
> be allocating sizeof(void *) which is 4 or 8 bytes depending on the
> architecture.
>
> Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>

Thanks.

I think your patch is right, but the code would be much simpler if we
actually did just allocate an array of struct imc_events, rather than an
array of pointers to structs.

Some of the cleanup code is written as if that is already the case, ie.
it frees the pmu->events array, but not the things the array points to.
So there's a memory leak there too.

Anju, Maddy, can one of you rework the code to just use an array of
structs? Basically imc_parse_event() wouldn't allocate a struct, we
would pass it a pointer to a slot in the array.

cheers

> diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
> index 88126245881b..91c90ddab807 100644
> --- a/arch/powerpc/perf/imc-pmu.c
> +++ b/arch/powerpc/perf/imc-pmu.c
> @@ -210,7 +210,7 @@ static int update_events_in_group(struct device_node *node, struct imc_pmu *pmu)
>  	of_property_read_u32(node, "reg", &base_reg);
>  
>  	/* Allocate memory for the events */
> -	pmu->events = kcalloc(ct, sizeof(struct imc_events), GFP_KERNEL);
> +	pmu->events = kcalloc(ct, sizeof(*pmu->events), GFP_KERNEL);
>  	if (!pmu->events)
>  		return -ENOMEM;
>