Hi Joerg, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: fb57b1fabcb28f358901b2df90abd2b48abc1ca8 commit: 57dbf81f50c82a0ad895a57828ad1ab539785a25 [5896/10701] iommu/mediatek-v1 Convert to probe/release_device() call-backs config: arm-randconfig-r013-20200519 (attached as .config) compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout 57dbf81f50c82a0ad895a57828ad1ab539785a25 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): drivers/iommu/mtk_iommu_v1.c: In function 'mtk_iommu_release_device': 467 | struct mtk_iommu_data *data; | ^~~~ vim +/data +467 drivers/iommu/mtk_iommu_v1.c b17336c55d8928 Honghui Zhang 2016-06-08 463 57dbf81f50c82a Joerg Roedel 2020-04-29 464 static void mtk_iommu_release_device(struct device *dev) b17336c55d8928 Honghui Zhang 2016-06-08 465 { a9bf2eec5a6fc0 Joerg Roedel 2018-11-29 466 struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); 6f66ea099fc2f3 Joerg Roedel 2017-03-31 @467 struct mtk_iommu_data *data; 6f66ea099fc2f3 Joerg Roedel 2017-03-31 468 a9bf2eec5a6fc0 Joerg Roedel 2018-11-29 469 if (!fwspec || fwspec->ops != &mtk_iommu_ops) b17336c55d8928 Honghui Zhang 2016-06-08 470 return; b17336c55d8928 Honghui Zhang 2016-06-08 471 3524b5592cad63 Joerg Roedel 2020-03-26 472 data = dev_iommu_priv_get(dev); 84672f192671e6 Robin Murphy 2016-10-17 473 iommu_fwspec_free(dev); b17336c55d8928 Honghui Zhang 2016-06-08 474 } b17336c55d8928 Honghui Zhang 2016-06-08 475 :::::: The code at line 467 was first introduced by commit :::::: 6f66ea099fc2f31d31d6cd39f3b13b23bdeb6196 iommu/mediatek: Teach MTK-IOMMUv1 about 'struct iommu_device' :::::: TO: Joerg Roedel <jroedel(a)suse.de&gt; :::::: CC: Joerg Roedel <jroedel(a)suse.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org