Hi John, First bad commit (maybe != root cause): tree: https://android.googlesource.com/kernel/common android12-5.10 head: d50b67ac7551b81ae82e70c6f2811073ba3575ba commit: 23762f02e172f146ccd160e36ed43483f2304aaf [3/5] ANDROID: dma-buf: system_heap: Add pagepool support to system heap config: arm64-randconfig-r025-20210209 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project c9439ca36342fb6013187d0a69aef92736951476) 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 arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu git remote add android-common https://android.googlesource.com/kernel/common git fetch --no-tags android-common android12-5.10 git checkout 23762f02e172f146ccd160e36ed43483f2304aaf # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 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 >>): int dmabuf_page_pool_init_shrinker(void) ^ drivers/dma-buf/heaps/page_pool.c:242:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int dmabuf_page_pool_init_shrinker(void) ^ static 1 warning generated. vim +/dmabuf_page_pool_init_shrinker +242 drivers/dma-buf/heaps/page_pool.c e7dac4c3231c0e John Stultz 2020-10-02 241 e7dac4c3231c0e John Stultz 2020-10-02 @242 int dmabuf_page_pool_init_shrinker(void) :::::: The code at line 242 was first introduced by commit :::::: e7dac4c3231c0e8adeef8dbb732b2cde7c162b14 ANDROID: dma-buf: heaps: Add a shrinker controlled page pool :::::: TO: John Stultz <john.stultz(a)linaro.org&gt; :::::: CC: Hridya Valsaraju <hridya(a)google.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org