Hi Dan, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm.git libnvdimm-pending head: 4e2f899e682d1e6c647651bc36bcdba3b3577485 commit: ff99d8c56c8e8d60122b87333e3b807fd1638431 [286/291] ACPI: Drop rcu usage for MMIO mappings config: ia64-randconfig-r025-20200519 (attached as .config) compiler: ia64-linux-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 ff99d8c56c8e8d60122b87333e3b807fd1638431 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64 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/acpi/osl.c: In function 'acpi_os_vprintf': drivers/acpi/osl.c:151:2: warning: function 'acpi_os_vprintf' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format] 151 | vsprintf(buffer, fmt, args); | ^~~~~~~~ drivers/acpi/osl.c: In function 'acpi_os_write_memory': 769 | acpi_status status; | ^~~~~~ vim +/status +769 drivers/acpi/osl.c d2b7355684cdcf Dan Williams 2020-05-13 764 e615bf5b551986 Myron Stowe 2012-01-20 765 acpi_status 653f4b538f66d3 Bob Moore 2012-02-14 766 acpi_os_write_memory(acpi_physical_address phys_addr, u64 value, u32 width) e615bf5b551986 Myron Stowe 2012-01-20 767 { e615bf5b551986 Myron Stowe 2012-01-20 768 unsigned int size = width / 8; d2b7355684cdcf Dan Williams 2020-05-13 @769 acpi_status status; ff99d8c56c8e8d Dan Williams 2020-04-27 770 bool did_fallback = false; ff99d8c56c8e8d Dan Williams 2020-04-27 771 void __iomem *virt_addr; e615bf5b551986 Myron Stowe 2012-01-20 772 ff99d8c56c8e8d Dan Williams 2020-04-27 773 virt_addr = acpi_os_rw_map(phys_addr, size, &did_fallback); e615bf5b551986 Myron Stowe 2012-01-20 774 if (!virt_addr) e615bf5b551986 Myron Stowe 2012-01-20 775 return AE_BAD_ADDRESS; e615bf5b551986 Myron Stowe 2012-01-20 776 d2b7355684cdcf Dan Williams 2020-05-13 777 status = acpi_os_write_iomem(virt_addr, value, width); e615bf5b551986 Myron Stowe 2012-01-20 778 ff99d8c56c8e8d Dan Williams 2020-04-27 779 acpi_os_rw_unmap(virt_addr, did_fallback); ff99d8c56c8e8d Dan Williams 2020-04-27 780 return AE_OK; e615bf5b551986 Myron Stowe 2012-01-20 781 } e615bf5b551986 Myron Stowe 2012-01-20 782 :::::: The code at line 769 was first introduced by commit :::::: d2b7355684cdcf842a9853915ae1c4927ae9a80a ACPI: Store pre-mapped registers in APEI entries :::::: TO: Dan Williams <dan.j.williams(a)intel.com&gt; :::::: CC: Dan Williams <dan.j.williams(a)intel.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org