Re: [PATCH] arm_pmu: fix compiler warning in arm_pmu_device_probe

[Chris Packham]

On 02/08/18 23:05, Will Deacon wrote:
> On Thu, Aug 02, 2018 at 09:45:26AM +1200, Chris Packham wrote:
>> GCC warns
>>
>>    arm_pmu_platform.c:234:5: error: 'err' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>>
>> This is because we rely on the for_each_cpu loop in armpmu_request_irqs
>> to initialise err. The warning is a little bogus because we know if
>> there were 0 CPUs this code would not be running.
>>
>> Initialise err to 0 to avoid the warning.
>>
>> Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
>> ---
>> This has been reported before in https://lkml.org/lkml/2018/3/5/508 I'm not
>> sure if it was dismmissed as "meh, gcc is wrong" or if it was just wainting for
>> someone with some round tuits.
> 
> Which version of GCC are you using? I don't see this warning locally.
> 

My local cross-compiler is

$ arm-softfloat-linux-gnueabi-gcc --version
arm-softfloat-linux-gnueabi-gcc (crosstool-NG crosstool-ng-1.22.0) 4.9.3

Old-ish but as far as I was aware still supported for building the kernel.

I've just tried 7.3.0 and 8.1.0 neither of which complain.

A quick look at the report linked to above seems they probably were 
using 4.6.3 and it still appears in current build reports

http://kisskb.ellerman.id.au/kisskb/buildresult/13455291/