Hi Nico,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on linus/master]
[also build test ERROR on v6.1]
[cannot apply to akpm-mm/mm-everything next-20221213]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Nico-Pache/mm-add-the-zero-case-to-page-1-compound_nr-in-set_compound_order/20221214-074610
patch link:    https://lore.kernel.org/r/20221213234505.173468-1-npache%40redhat.com
patch subject: [RFC V2] mm: add the zero case to page[1].compound_nr in set_compound_order
config: arc-allyesconfig
compiler: arceb-elf-gcc (GCC) 12.1.0
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
        # https://github.com/intel-lab-lkp/linux/commit/a85dc610bdd079bf6e9a791c2e3c33730cab89ed
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Nico-Pache/mm-add-the-zero-case-to-page-1-compound_nr-in-set_compound_order/20221214-074610
        git checkout a85dc610bdd079bf6e9a791c2e3c33730cab89ed
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/linux/scatterlist.h:8,
                    from include/linux/dma-mapping.h:10,
                    from drivers/net/wwan/t7xx/t7xx_pci.c:23:
   include/linux/mm.h: In function 'set_compound_order':
>> include/linux/mm.h:941:23: error: unused variable 'shift' [-Werror=unused-variable]
     941 |         unsigned long shift = (1U << order);
         |                       ^~~~~
   cc1: all warnings being treated as errors
--
   In file included from arch/arc/include/asm/cacheflush.h:18,
                    from include/linux/cacheflush.h:5,
                    from include/linux/highmem.h:8,
                    from include/linux/bvec.h:10,
                    from include/linux/skbuff.h:17,
                    from include/net/net_namespace.h:43,
                    from include/linux/netdevice.h:38,
                    from drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c:22:
   include/linux/mm.h: In function 'set_compound_order':
>> include/linux/mm.h:941:23: error: unused variable 'shift' [-Werror=unused-variable]
     941 |         unsigned long shift = (1U << order);
         |                       ^~~~~
   during RTL pass: mach
   drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c: In function 't7xx_port_enum_msg_handler':
   drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c:156:1: internal compiler error: in arc_ifcvt, at config/arc/arc.cc:9642
     156 | }
         | ^
   0x59b7d9 arc_ifcvt
   	/tmp/build-crosstools-gcc-12.1.0-binutils-2.38/gcc/gcc-12.1.0/gcc/config/arc/arc.cc:9642
   0xdeaf74 arc_reorg
   	/tmp/build-crosstools-gcc-12.1.0-binutils-2.38/gcc/gcc-12.1.0/gcc/config/arc/arc.cc:8424
   0xaaab69 execute
   	/tmp/build-crosstools-gcc-12.1.0-binutils-2.38/gcc/gcc-12.1.0/gcc/reorg.cc:3927
   Please submit a full bug report, with preprocessed source (by using -freport-bug).
   Please include the complete backtrace with any bug report.
   See <https://gcc.gnu.org/bugs/> for instructions.


vim +/shift +941 include/linux/mm.h

   938	
   939	static inline void set_compound_order(struct page *page, unsigned int order)
   940	{
 > 941		unsigned long shift = (1U << order);
   942		page[1].compound_order = order;
   943	#ifdef CONFIG_64BIT
   944		// Branchless conditional:
   945		// order  > 0 --> compound_nr = shift
   946		// order == 0 --> compound_nr = 0
   947		page[1].compound_nr = shift ^ (-order  ^ shift) & shift;
   948	#endif
   949	}
   950	

-- 
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https://01.org/lkp