Re: [PATCH V3 1/3] iommu/arm-smmu-v3: Add device-tree support for CMDQV driver

[Robin Murphy <robin.murphy@arm.com>]

On 2025-12-03 11:04 am, Ashish Mhetre wrote:
> 
> On 12/3/2025 2:05 PM, kernel test robot wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> Hi Ashish,
>>
>> kernel test robot noticed the following build errors:
>>
>> [auto build test ERROR on next-20251201]
>> [also build test ERROR on v6.18]
>> [cannot apply to robh/for-next linus/master v6.18 v6.18-rc7 v6.18-rc6]
>> [If your patch is applied to the wrong git tree, kindly drop us a note.
>> And when submitting patch, we suggest to use '--base' as documented in
>> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>>
>> url:    https://github.com/intel-lab-lkp/linux/commits/Ashish-Mhetre/ 
>> iommu-arm-smmu-v3-Add-device-tree-support-for-CMDQV- 
>> driver/20251202-003517
>> base:   next-20251201
>> patch link:    https://lore.kernel.org/r/20251201163219.3237266-2- 
>> amhetre%40nvidia.com
>> patch subject: [PATCH V3 1/3] iommu/arm-smmu-v3: Add device-tree 
>> support for CMDQV driver
>> config: arm64-allmodconfig (https://download.01.org/0day-ci/ 
>> archive/20251203/202512031601.IpliwbHW-lkp@intel.com/config)
>> compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project 
>> cd708029e0b2869e80abe31ddb175f7c35361f90)
>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/ 
>> archive/20251203/202512031601.IpliwbHW-lkp@intel.com/reproduce)
>>
>> If you fix the issue in a separate patch/commit (i.e. not just a new 
>> version of
>> the same patch/commit), kindly add following tags
>> | Reported-by: kernel test robot <lkp@intel.com>
>> | Closes: https://lore.kernel.org/oe-kbuild-all/202512031601.IpliwbHW- 
>> lkp@intel.com/
>>
>> All errors (new ones prefixed by >>):
>>
>>>> ld.lld: error: duplicate symbol: init_module
>>     >>> defined at arm-smmu-v3.c
>>     >>>            drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.o: 
>> (init_module)
>>     >>> defined at tegra241-cmdqv.c
>>     >>>            drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.o: 
>> (.init.text+0x4)
>> -- 
>>>> ld.lld: error: duplicate symbol: cleanup_module
>>     >>> defined at arm-smmu-v3.c
>>     >>>            drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.o: 
>> (cleanup_module)
>>     >>> defined at tegra241-cmdqv.c
>>     >>>            drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.o: 
>> (.exit.text+0x4)
> 
> Hi Nic, Robin,
> 
> How do you suggest fixing this? Is it fine to compile tegra241-cmdqv as 
> separate module
> and export tegra241_cmdqv_probe() to fix this warning?

As Jon just pointed out, the issue is using module_platform_driver(), 
which is unnecessary anyway since this is not a driver; nor is it even a 
module, it's just some extra code that can be included in the 
arm_smmu_v3 driver, and will be integral to the arm_smmu_v3.ko module if 
built as a such.

You could sanity-check the compatible of the phandle target in 
tegra_cmdqv_dt_probe() if you feel like you should do more than just 
blindly trust the DT, but either way trying to register a dummy platform 
driver that won't bind to anything is pointless.

> I am using GCC compiler and was not able to reproduce this with W=1 build.

This will be happening with CONFIG_ARM_SMMU_V3=m.

Thanks,
Robin.

> 
> Thanks,
> Ashish Mhetre
> 
>> -- 
>> 0-DAY CI Kernel Test Service
>> https://github.com/intel/lkp-tests/wiki