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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id s4-20020a817704000000b0057a5302e2fesm373645ywc.5.2023.07.06.13.28.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Jul 2023 13:28:20 -0700 (PDT) Date: Thu, 6 Jul 2023 13:28:11 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Geert Uytterhoeven cc: Hugh Dickins , linux-m68k@lists.linux-m68k.org, oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, Andrew Morton , Linux Memory Management List Subject: Re: arch/m68k/include/asm/mmu_context.h:164 load_ksp_mmu() warn: unsigned 'mmuar' is never less than zero. In-Reply-To: <202307061849.rJKwVbXb-lkp@intel.com> Message-ID: <11ff8d26-8dbb-6d3a-c488-fd357098414@google.com> References: <202307061849.rJKwVbXb-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: DAC9740003 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: dnsmhnjgsnsurr4z7d6hjjo85t5wai9r X-HE-Tag: 1688675301-714529 X-HE-Meta: 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 80mW1Mrh 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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@intel.com/config) > compiler: m68k-linux-gcc (GCC) 12.3.0 > reproduce: (https://download.01.org/0day-ci/archive/20230706/202307061849.rJKwVbXb-lkp@intel.com/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 > | Closes: https://lore.kernel.org/oe-kbuild-all/202307061849.rJKwVbXb-lkp@intel.com/ > > 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