Re: [PATCH] powerpc/perf: double unlock bug in imc_common_cpuhp_mem_free()

[Madhavan Srinivasan <maddy@linux.vnet.ibm.com>]

On Saturday 12 August 2017 01:35 AM, Dan Carpenter wrote:
> There is a typo so we call unlock instead of lock.

Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>

nest_imc_refc used to maintain list of perf sessions thats using the
nest units currently. This is needed in turning off nest engine microcode
when not in use.

Yes will send a patch to fix ref->lock change.

Thanks for fix

Maddy

>
> Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> I also don't understand how the &nest_imc_refc[node_id].lock works.  Why
> can't we use ref->lock everywhere?  They seem equivalent, and my static
> checker complains if we call the same lock different names.
>
> diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
> index 46cd912af060..52017f6eafd9 100644
> --- a/arch/powerpc/perf/imc-pmu.c
> +++ b/arch/powerpc/perf/imc-pmu.c
> @@ -1124,7 +1124,7 @@ static void cleanup_all_thread_imc_memory(void)
>   static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
>   {
>   	if (pmu_ptr->domain == IMC_DOMAIN_NEST) {
> -		mutex_unlock(&nest_init_lock);
> +		mutex_lock(&nest_init_lock);
>   		if (nest_pmus == 1) {
>   			cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
>   			kfree(nest_imc_refc);
>