Hi Claudio, I love your patch! Perhaps something to improve: [auto build test WARNING on kvm/queue] [also build test WARNING on v5.17-rc2 next-20220204] [cannot apply to kvms390/next s390/features] [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] url: https://github.com/0day-ci/linux/commits/Claudio-Imbrenda/KVM-s390-pv-implement-lazy-destroy-for-reboot/20220204-235609 base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue config: s390-randconfig-r044-20220131 (https://download.01.org/0day-ci/archive/20220205/202202050319.tZ4OT36V-lkp@xxxxxxxxx/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project a73e4ce6a59b01f0e37037761c1e6889d539d233) 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 s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://github.com/0day-ci/linux/commit/cc87a31d00bc8f7a4e95369503a5ce184747a32b git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Claudio-Imbrenda/KVM-s390-pv-implement-lazy-destroy-for-reboot/20220204-235609 git checkout cc87a31d00bc8f7a4e95369503a5ce184747a32b # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash arch/s390/kvm/ arch/s390/mm/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): In file included from arch/s390/mm/fault.c:36: In file included from arch/s390/include/asm/diag.h:12: In file included from include/linux/if_ether.h:19: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x)) ^ include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16' #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) ^ In file included from arch/s390/mm/fault.c:36: In file included from arch/s390/include/asm/diag.h:12: In file included from include/linux/if_ether.h:19: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32' #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) ^ In file included from arch/s390/mm/fault.c:36: In file included from arch/s390/include/asm/diag.h:12: In file included from include/linux/if_ether.h:19: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ >> arch/s390/mm/fault.c:805:18: warning: variable 'mm' is uninitialized when used here [-Wuninitialized] mmap_read_lock(mm); ^~ arch/s390/mm/fault.c:771:22: note: initialize the variable 'mm' to silence this warning struct mm_struct *mm; ^ = NULL 13 warnings generated. vim +/mm +805 arch/s390/mm/fault.c 766 767 void do_secure_storage_access(struct pt_regs *regs) 768 { 769 unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK; 770 struct vm_area_struct *vma; 771 struct mm_struct *mm; 772 struct page *page; 773 struct gmap *gmap; 774 int rc; 775 776 /* 777 * bit 61 tells us if the address is valid, if it's not we 778 * have a major problem and should stop the kernel or send a 779 * SIGSEGV to the process. Unfortunately bit 61 is not 780 * reliable without the misc UV feature so we need to check 781 * for that as well. 782 */ 783 if (test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications) && 784 !test_bit_inv(61, ®s->int_parm_long)) { 785 /* 786 * When this happens, userspace did something that it 787 * was not supposed to do, e.g. branching into secure 788 * memory. Trigger a segmentation fault. 789 */ 790 if (user_mode(regs)) { 791 send_sig(SIGSEGV, current, 0); 792 return; 793 } 794 795 /* 796 * The kernel should never run into this case and we 797 * have no way out of this situation. 798 */ 799 panic("Unexpected PGM 0x3d with TEID bit 61=0"); 800 } 801 802 switch (get_fault_type(regs)) { 803 case GMAP_FAULT: 804 gmap = (struct gmap *)S390_lowcore.gmap; > 805 mmap_read_lock(mm); 806 addr = __gmap_translate(gmap, addr); 807 mmap_read_unlock(mm); 808 if (IS_ERR_VALUE(addr)) { 809 do_fault_error(regs, VM_ACCESS_FLAGS, VM_FAULT_BADMAP); 810 break; 811 } 812 fallthrough; 813 case USER_FAULT: 814 mm = current->mm; 815 mmap_read_lock(mm); 816 vma = find_vma(mm, addr); 817 if (!vma) { 818 mmap_read_unlock(mm); 819 do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); 820 break; 821 } 822 page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET); 823 if (IS_ERR_OR_NULL(page)) { 824 mmap_read_unlock(mm); 825 break; 826 } 827 if (arch_make_page_accessible(page)) 828 send_sig(SIGSEGV, current, 0); 829 put_page(page); 830 mmap_read_unlock(mm); 831 break; 832 case KERNEL_FAULT: 833 page = phys_to_page(addr); 834 if (unlikely(!try_get_page(page))) 835 break; 836 rc = arch_make_page_accessible(page); 837 put_page(page); 838 if (rc) 839 BUG(); 840 break; 841 default: 842 do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); 843 WARN_ON_ONCE(1); 844 } 845 } 846 NOKPROBE_SYMBOL(do_secure_storage_access); 847 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
