tree: https://github.com/luxis1999/iommufd iommufd-v5.17-rc1 head: ebf68af0385d0d5c209e63e8065d31db938275d8 commit: 68a771c26362267465beafd67fabe1e751604493 [23/28] vfio/pci: Add VFIO_DEVICE_ATTACH_IOASPT config: i386-randconfig-a003 (https://download.01.org/0day-ci/archive/20220210/202202100016.xxWqSxcW-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/luxis1999/iommufd/commit/68a771c26362267465beafd67fabe... git remote add luxis1999-iommufd https://github.com/luxis1999/iommufd git fetch --no-tags luxis1999-iommufd iommufd-v5.17-rc1 git checkout 68a771c26362267465beafd67fabe1e751604493 # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/vfio/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from drivers/vfio/vfio.c:35: 30 | { | ^ include/linux/iommufd.h:29:1: warning: 'iommufd_bind_pci_device' declared 'static' but never defined [-Wunused-function] 29 | iommufd_bind_pci_device(int fd, struct pci_dev *pdev, u32 *id); | ^~~~~~~~~~~~~~~~~~~~~~~ vim +30 include/linux/iommufd.h faffab36f0032f0 Jason Gunthorpe 2021-11-11 26 faffab36f0032f0 Jason Gunthorpe 2021-11-11 27 #else /* !CONFIG_IOMMUFD */ faffab36f0032f0 Jason Gunthorpe 2021-11-11 28 static inline struct iommufd_device * faffab36f0032f0 Jason Gunthorpe 2021-11-11 29 iommufd_bind_pci_device(int fd, struct pci_dev *pdev, u32 *id); faffab36f0032f0 Jason Gunthorpe 2021-11-11 @30 { faffab36f0032f0 Jason Gunthorpe 2021-11-11 31 return ERR_PTR(-EOPNOTSUPP); faffab36f0032f0 Jason Gunthorpe 2021-11-11 32 } faffab36f0032f0 Jason Gunthorpe 2021-11-11 33 :::::: The code at line 30 was first introduced by commit :::::: faffab36f0032f06ff2478067840ead66e38b543 iommufd: Add kAPI toward external drivers :::::: TO: Jason Gunthorpe <jgg(a)nvidia.com&gt; :::::: CC: Jason Gunthorpe <jgg(a)nvidia.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org