On 03/13/2018 11:15 PM, kbuild test robot wrote: > tree: git://git.cmpxchg.org/linux-mmotm.git master > head: ead058c4ec49752a4e0323368f1d695385c66020 > commit: af7abfba1161d2814301844fe11adac16910ea80 [8/285] hugetlbfs-check-for-pgoff-value-overflow-v3 > config: sh-defconfig (attached as .config) > compiler: sh4-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0 > reproduce: > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > git checkout af7abfba1161d2814301844fe11adac16910ea80 > # save the attached .config to linux build tree > make.cross ARCH=sh > > All warnings (new ones prefixed by >>): > > fs//hugetlbfs/inode.c: In function 'hugetlbfs_file_mmap': >>> fs//hugetlbfs/inode.c:118:36: warning: left shift count is negative [-Wshift-count-negative] > #define PGOFF_LOFFT_MAX (PAGE_MASK << (BITS_PER_LONG - (2 * PAGE_SHIFT) - 1)) > ^ BITS_PER_LONG = 32 (32bit config) PAGE_SHIFT = 16 (64K pages) This results in the negative shift value. I had proposed another (not so pretty way) to create the mask. #define PGOFF_LOFFT_MAX \ (((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1))) This works for the above config, and should work for any. Andrew, how would you like me to update the patch? I can send a new version but know you have also made some changes for VM_WARN. Would you simply like a delta on top of the current patch? -- Mike Kravetz
