[bug report] perf: xgene: Add APM X-Gene SoC Performance Monitoring Unit driver

Tai Tri Nguyen
2016-10-12T15:28:54Z

Hi Mark,

Sure I'm working on it.

Regards,
Tai

On Wed, Oct 12, 2016 at 8:23 AM, Mark Rutland <mark.rutland@arm.com> wrote:
> Hi Dan,
>
> Thanks for the report.
>
> On Wed, Oct 12, 2016 at 02:32:29PM +0300, Dan Carpenter wrote:
>> The patch 832c927d119b: "perf: xgene: Add APM X-Gene SoC Performance
>> Monitoring Unit driver" from Jul 15, 2016, leads to the following
>> static checker warning:
>>
>> drivers/perf/xgene_pmu.c:1014 acpi_get_pmu_hw_inf()
>> warn: '&res' isn't an ERR_PTR
>>
>> drivers/perf/xgene_pmu.c
>> 992 static struct
>> 993 xgene_pmu_dev_ctx *acpi_get_pmu_hw_inf(struct xgene_pmu *xgene_pmu,
>> 994 struct acpi_device *adev, u32 type)
>> 995 {
>> 996 struct device *dev = xgene_pmu->dev;
>> 997 struct list_head resource_list;
>> 998 struct xgene_pmu_dev_ctx *ctx;
>> 999 const union acpi_object *obj;
>> 1000 struct hw_pmu_info *inf;
>> 1001 void __iomem *dev_csr;
>> 1002 struct resource res;
>> 1003 int enable_bit;
>> 1004 int rc;
>> 1005
>> 1006 ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
>> 1007 if (!ctx)
>> 1008 return NULL;
>> 1009
>> 1010 INIT_LIST_HEAD(&resource_list);
>> 1011 rc = acpi_dev_get_resources(adev, &resource_list,
>> 1012 acpi_pmu_dev_add_resource, &res);
>> 1013 acpi_dev_free_resource_list(&resource_list);
>> 1014 if (rc < 0 || IS_ERR(&res)) {
>> ^^^^
>> Obviously this is a stack address and not an error pointer. I'm not
>> sure what was intended here.
>
> Urrgh; I should have caught that in review. It's been this way since v1 [1], so
> I can't reverse-engineer the intent. However, I don't believe that it's
> necessary to check anything other than the rc value here.
>
> This should always evaluate as false, and shouldn't result in a functional
> problem, but it is completely bogus.
>
> Tai, can you plase send a patch deleting The IS_ERR() check here?
>
> Thanks,
> Mark.
>
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-March/419173.html

--
Tai