[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 at arm.com>
> Cc: Mark Rutland <mark.rutland at arm.com>
> Signed-off-by: Will Deacon <will.deacon at 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
>