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

[Madhavan Srinivasan]

On Monday 14 August 2017 09:00 AM, Michael Ellerman wrote:

Dan Carpenter  writes:


There is a typo so we call unlock instead of lock.

Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
Signed-off-by: Dan Carpenter 
---
I also don't understand how the _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.

That looks like a bug to me, ie. we should always use ref.


ok. will send a fix.

Thanks
Maddy



Maddy?

cheers


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(_init_lock);
+   mutex_lock(_init_lock);
if (nest_pmus == 1) {

cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
kfree(nest_imc_refc);

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

[Madhavan Srinivasan]

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 

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 
---
I also don't understand how the _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(_init_lock);
+   mutex_lock(_init_lock);
if (nest_pmus == 1) {

cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
kfree(nest_imc_refc);

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

[Michael Ellerman]

Dan Carpenter  writes:

> There is a typo so we call unlock instead of lock.
>
> Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
> Signed-off-by: Dan Carpenter 
> ---
> I also don't understand how the _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.

That looks like a bug to me, ie. we should always use ref.

Maddy?

cheers

> 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(_init_lock);
> + mutex_lock(_init_lock);
>   if (nest_pmus == 1) {
>   
> cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
>   kfree(nest_imc_refc);