Hi Andrew, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: d5b2251d63b5344ee827d3680fa79bdb9f9ddfa1 commit: a9770eac511ad82390b9f4a3c1728e078c387ac7 [3068/7089] net: mdio: Move MDIO drivers into a new subdirectory config: x86_64-randconfig-a014-20200912 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 45d0343900d3005d1d00cbb1a87c419c085dec71) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git checkout a9770eac511ad82390b9f4a3c1728e078c387ac7 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): drivers/net/mdio/mdio-xgene.c:337:13: warning: cast to smaller integer type 'enum xgene_mdio_id' from 'const void *' [-Wvoid-pointer-to-enum-cast] mdio_id = (enum xgene_mdio_id)of_id->data; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ static const struct of_device_id xgene_mdio_of_match[] = { ^ 2 warnings generated. # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout a9770eac511ad82390b9f4a3c1728e078c387ac7 vim +/xgene_mdio_of_match +302 drivers/net/mdio/mdio-xgene.c 43b3cf6634a4ae2 drivers/net/phy/mdio-xgene.c Iyappan Subramanian 2016-07-25 301 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 @302 static const struct of_device_id xgene_mdio_of_match[] = { 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 303 { 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 304 .compatible = "apm,xgene-mdio-rgmii", 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 305 .data = (void *)XGENE_MDIO_RGMII 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 306 }, 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 307 { 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 308 .compatible = "apm,xgene-mdio-xfi", 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 309 .data = (void *)XGENE_MDIO_XFI 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 310 }, 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 311 {}, 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 312 }; 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 313 MODULE_DEVICE_TABLE(of, xgene_mdio_of_match); 1f3d62090d3ba4d drivers/net/phy/mdio-xgene.c Arnd Bergmann 2017-02-01 314 :::::: The code at line 302 was first introduced by commit :::::: 1f3d62090d3ba4d0c14e5271be87812fc577b197 xgene_enet: remove bogus forward declarations :::::: TO: Arnd Bergmann <arnd(a)arndb.de&gt; :::::: CC: David S. Miller <davem(a)davemloft.net&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org