On 16/05/15 08:09, Ingo Molnar wrote:
>
> * Colin King <[email protected]> wrote:
>
>> From: Colin Ian King <[email protected]>
>>
>> Recent commit 3b8786ff7a1b31645ae2c26a2ec32dbd42ac1094
>> ("ARM: 8352/1: perf: Fix the pmu node name in warning message")
>> introduced a memory leak of irqs on the "Don't bother with PPIs"
>> return path. This was picked up by static analysis by cppcheck:
>>
>> [arch/arm/kernel/perf_event_cpu.c:315]: (error) Memory leak: irqs
>>
>> simpele fix is to free irqs when returning.
>>
>> Signed-off-by: Colin Ian King <[email protected]>
>> ---
>> arch/arm/kernel/perf_event_cpu.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/kernel/perf_event_cpu.c
>> b/arch/arm/kernel/perf_event_cpu.c
>> index 213919b..9e5b2a5 100644
>> --- a/arch/arm/kernel/perf_event_cpu.c
>> +++ b/arch/arm/kernel/perf_event_cpu.c
>> @@ -311,8 +311,10 @@ static int of_pmu_irq_cfg(struct platform_device *pdev)
>>
>> /* Don't bother with PPIs; they're already affine */
>> irq = platform_get_irq(pdev, 0);
>> - if (irq >= 0 && irq_is_percpu(irq))
>> + if (irq >= 0 && irq_is_percpu(irq)) {
>> + kfree(irqs);
>> return 0;
>> + }
>>
>> for (i = 0; i < pdev->num_resources; ++i) {
>> struct device_node *dn;
>
> So returning from the middle of a function isn't very clean.
>
> Also, why do we return 0 in an error case?
I believe that's explained in commit
338d9dd3e2aee00a9198e8bf6e7d535d3feeaf32 ("ARM: 8351/1: perf: don't warn
about missing interrupt-affinity property for PPIs"):
"PPIs are affine by nature, so the interrupt-affinity property is not
used and therefore we shouldn't print a warning in its absence."
>
> Furthermore, this function already has a (partially hidden) error
> cleanup path:
>
> if (i == pdev->num_resources)
> cpu_pmu->irq_affinity = irqs;
> else
> kfree(irqs);
>
> So this code should use proper goto driven cleanup. That's faster and
> cleaner, and is less likely to result in bugs like the above.
>
> Thanks,
>
> Ingo
>
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