Hi Geert, On Thu, 6 Jul 2023, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > head: c17414a273b81fe4e34e11d69fc30cc8b1431614 > commit: e67b37c368b7cc24b8c0fe5ab6c44422312eab37 m68k: allow pte_offset_map[_lock]() to fail > date: 2 weeks ago > config: m68k-randconfig-m031-20230706 (https://download.01.org/0day-ci/archive/20230706/202307061849.rJKwVbXb-lkp@xxxxxxxxx/config) > compiler: m68k-linux-gcc (GCC) 12.3.0 > reproduce: (https://download.01.org/0day-ci/archive/20230706/202307061849.rJKwVbXb-lkp@xxxxxxxxx/reproduce) > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > | Closes: https://lore.kernel.org/oe-kbuild-all/202307061849.rJKwVbXb-lkp@xxxxxxxxx/ > > New smatch warnings: > arch/m68k/include/asm/mmu_context.h:164 load_ksp_mmu() warn: unsigned 'mmuar' is never less than zero. > > Old smatch warnings: > arch/m68k/include/asm/mmu_context.h:114 load_ksp_mmu() warn: always true condition '(mmuar >= (0)) => (0-u32max >= 0)' > arch/m68k/include/asm/mmu_context.h:140 load_ksp_mmu() warn: always true condition '(mmuar >= (0)) => (0-u32max >= 0)' > > vim +/mmuar +164 arch/m68k/include/asm/mmu_context.h > > 92 > 93 static inline void load_ksp_mmu(struct task_struct *task) > 94 { > 95 unsigned long flags; > 96 struct mm_struct *mm; > 97 int asid; > 98 pgd_t *pgd; > 99 p4d_t *p4d; > 100 pud_t *pud; > 101 pmd_t *pmd; > 102 pte_t *pte = NULL; > 103 unsigned long mmuar; > 104 > 105 local_irq_save(flags); > 106 mmuar = task->thread.ksp; > 107 > 108 /* Search for a valid TLB entry, if one is found, don't remap */ > 109 mmu_write(MMUAR, mmuar); > 110 mmu_write(MMUOR, MMUOR_STLB | MMUOR_ADR); > 111 if (mmu_read(MMUSR) & MMUSR_HIT) > 112 goto end; > 113 > 114 if (mmuar >= PAGE_OFFSET) { > 115 mm = &init_mm; > 116 } else { > 117 pr_info("load_ksp_mmu: non-kernel mm found: 0x%p\n", task->mm); > 118 mm = task->mm; > 119 } > 120 > 121 if (!mm) > 122 goto bug; > 123 > 124 pgd = pgd_offset(mm, mmuar); > 125 if (pgd_none(*pgd)) > 126 goto bug; > 127 > 128 p4d = p4d_offset(pgd, mmuar); > 129 if (p4d_none(*p4d)) > 130 goto bug; > 131 > 132 pud = pud_offset(p4d, mmuar); > 133 if (pud_none(*pud)) > 134 goto bug; > 135 > 136 pmd = pmd_offset(pud, mmuar); > 137 if (pmd_none(*pmd)) > 138 goto bug; > 139 > 140 pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar) > 141 : pte_offset_map(pmd, mmuar); > 142 if (!pte || pte_none(*pte) || !pte_present(*pte)) > 143 goto bug; > 144 > 145 set_pte(pte, pte_mkyoung(*pte)); > 146 asid = mm->context & 0xff; > 147 if (!pte_dirty(*pte) && mmuar <= PAGE_OFFSET) > 148 set_pte(pte, pte_wrprotect(*pte)); > 149 > 150 mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | > 151 (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK) > 152 >> CF_PAGE_MMUTR_SHIFT) | MMUTR_V); > 153 > 154 mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) | > 155 ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X); > 156 > 157 mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA); > 158 > 159 goto end; > 160 > 161 bug: > 162 pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar); > 163 end: > > 164 if (pte && mmuar < PAGE_OFFSET) > 165 pte_unmap(pte); > 166 local_irq_restore(flags); > 167 } > 168 > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki I'm sorry, it appears that I've increased the number of smatch warnings on m68k: but since it was already complaining about "mmuar >= PAGE_OFFSET"s there, I'm not going to feel very guilty about my "mmuar < PAGE_OFFSET"; and I've no idea of the significance of PAGE_OFFSET 0 on m68k. Over to you - but I expect ignoring this will continue to be the right answer :) Thanks, Hugh
