[PATCH RESEND] drivers/perf: arm_pmu: avoid CPU device_node reference leak

[PATCH RESEND] drivers/perf: arm_pmu: avoid CPU device_node reference leak

[Will Deacon]

of_cpu_device_node_get increments the reference count on the CPU
device_node, so we must take care to of_node_put once we've finished
with it.

This patch fixes the perf IRQ probing code to avoid the leak.

Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---

Arnd/Olof: Please can you take this via arm-soc? It's a non-urgent, yet
           simple fix and I don't have any other fixes queued for perf.

 drivers/perf/arm_pmu.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 2365a32a595e..be3755c973e9 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -823,9 +823,15 @@ static int of_pmu_irq_cfg(struct arm_pmu *pmu)
 		}
 
 		/* Now look up the logical CPU number */
-		for_each_possible_cpu(cpu)
-			if (dn == of_cpu_device_node_get(cpu))
+		for_each_possible_cpu(cpu) {
+			struct device_node *cpu_dn;
+
+			cpu_dn = of_cpu_device_node_get(cpu);
+			of_node_put(cpu_dn);
+
+			if (dn == cpu_dn)
 				break;
+		}
 
 		if (cpu >= nr_cpu_ids) {
 			pr_warn("Failed to find logical CPU for %s\n",
-- 
2.1.4

[PATCH RESEND] drivers/perf: arm_pmu: avoid CPU device_node reference leak

[Will Deacon]

On Mon, Oct 12, 2015 at 02:48:39PM +0100, Will Deacon wrote:
> of_cpu_device_node_get increments the reference count on the CPU
> device_node, so we must take care to of_node_put once we've finished
> with it.
> 
> This patch fixes the perf IRQ probing code to avoid the leak.
> 
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
> ---
> 
> Arnd/Olof: Please can you take this via arm-soc? It's a non-urgent, yet
>            simple fix and I don't have any other fixes queued for perf.

Ping? I can't see this queued in arm-soc and I'm away next week, so just
following up while I can.

Will

>  drivers/perf/arm_pmu.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
> index 2365a32a595e..be3755c973e9 100644
> --- a/drivers/perf/arm_pmu.c
> +++ b/drivers/perf/arm_pmu.c
> @@ -823,9 +823,15 @@ static int of_pmu_irq_cfg(struct arm_pmu *pmu)
>  		}
>  
>  		/* Now look up the logical CPU number */
> -		for_each_possible_cpu(cpu)
> -			if (dn == of_cpu_device_node_get(cpu))
> +		for_each_possible_cpu(cpu) {
> +			struct device_node *cpu_dn;
> +
> +			cpu_dn = of_cpu_device_node_get(cpu);
> +			of_node_put(cpu_dn);
> +
> +			if (dn == cpu_dn)
>  				break;
> +		}
>  
>  		if (cpu >= nr_cpu_ids) {
>  			pr_warn("Failed to find logical CPU for %s\n",
> -- 
> 2.1.4
> 

[PATCH RESEND] drivers/perf: arm_pmu: avoid CPU device_node reference leak

[Arnd Bergmann]

On Monday 12 October 2015 14:48:39 Will Deacon wrote:
> of_cpu_device_node_get increments the reference count on the CPU
> device_node, so we must take care to of_node_put once we've finished
> with it.
> 
> This patch fixes the perf IRQ probing code to avoid the leak.
> 
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
> ---
> 
> Arnd/Olof: Please can you take this via arm-soc? It's a non-urgent, yet
>            simple fix and I don't have any other fixes queued for perf.
> 

Seems still appropriate for 4.3, so I've put it into the fixes branch.
Thanks for the reminder,

	Arnd