Messages in this thread Patch in this message | | | Subject | Re: [PATCH] LoongArch: Add kernel address sanitizer support | From | Qing Zhang <> | Date | Thu, 30 Mar 2023 10:06:00 +0800 |
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Hi, Andrey On 2023/3/30 上午3:02, Andrey Konovalov wrote: >> diff --git a/include/linux/kasan.h b/include/linux/kasan.h >> index f7ef70661ce2..3b91b941873d 100644 >> --- a/include/linux/kasan.h >> +++ b/include/linux/kasan.h >> @@ -54,11 +54,13 @@ extern p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D]; >> int kasan_populate_early_shadow(const void *shadow_start, >> const void *shadow_end); >> >> +#ifndef __HAVE_ARCH_SHADOW_MAP >> static inline void *kasan_mem_to_shadow(const void *addr) >> { >> return (void *)((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT) >> + KASAN_SHADOW_OFFSET; >> } >> +#endif >> >> int kasan_add_zero_shadow(void *start, unsigned long size); >> void kasan_remove_zero_shadow(void *start, unsigned long size); >> diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c >> index e5eef670735e..f86194750df5 100644 >> --- a/mm/kasan/generic.c >> +++ b/mm/kasan/generic.c >> @@ -175,6 +175,11 @@ static __always_inline bool check_region_inline(unsigned long addr, >> if (unlikely(!addr_has_metadata((void *)addr))) >> return !kasan_report(addr, size, write, ret_ip); >> >> +#ifndef __HAVE_ARCH_SHADOW_MAP >> + if (unlikely(kasan_mem_to_shadow((unsigned long *)addr) == NULL)) >> + return !kasan_report(addr, size, write, ret_ip); >> +#endif > > This should have been ifdef, right? > Sorry, it was a clerical error, Here it is #ifndef __HAVE_ARCH_SHADOW_MAP if (unlikely(! addr_has_metadata((void *)addr))) return ! kasan_report(addr, size, write, ret_ip); #else if (unlikely(kasan_mem_to_shadow((void *)addr) == NULL)) { kasan_report(addr, size, write, ret_ip); return; } #endif > But I don't think you need this check here at all: addr_has_metadata > already checks that shadow exists. > On LongArch, there's a lot of holes between different segments, so kasan shadow area is some different type of memory that we concatenate, we can't use if (unlikely((void *)addr < kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) to determine the validity, and in arch/loongarch/include/asm/kasan.h I construct invalid NULL. >> + >> if (likely(!memory_is_poisoned(addr, size))) >> return true; >> >> diff --git a/mm/kasan/init.c b/mm/kasan/init.c >> index cc64ed6858c6..860061a22ca9 100644 >> --- a/mm/kasan/init.c >> +++ b/mm/kasan/init.c >> @@ -166,8 +166,9 @@ static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr, >> if (!p) >> return -ENOMEM; >> } else { >> - pud_populate(&init_mm, pud, >> - early_alloc(PAGE_SIZE, NUMA_NO_NODE)); >> + p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); >> + pmd_init(p); >> + pud_populate(&init_mm, pud, p); >> } >> } >> zero_pmd_populate(pud, addr, next); >> @@ -207,8 +208,9 @@ static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr, >> if (!p) >> return -ENOMEM; >> } else { >> - p4d_populate(&init_mm, p4d, >> - early_alloc(PAGE_SIZE, NUMA_NO_NODE)); >> + p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); >> + pud_init(p); >> + p4d_populate(&init_mm, p4d, p); > > Please explain why these changes are needed in the patch description.
This is because in pagetable_init on loongarch/mips, we populate pmd/pud with invalid_pmd_table/invalid_pud_table, So pmd_init/pud_init(p) is required, perhaps we define them as __weak in mm/kasan/init.c, like mm/sparse-vmemmap.c.
diff --git a/include/linux/mm.h b/include/linux/mm.h ... +void pmd_init(void *addr); +void pud_init(void *addr); ... diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c ... +void __weak __meminit pmd_init(void *addr) + { +} + @@-203,11 +207,16 @@pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node) void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); if (! p) return NULL; + pmd_init(p); pud_populate(&init_mm, pud, p); } return pud; } +void __weak __meminit pud_init(void *addr) + { +} + p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) { p4d_t *p4d = p4d_offset(pgd, addr); @@-215,6 +224,7 @@p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); if (! p) return NULL; + pud_init(p); p4d_populate(&init_mm, p4d, p); } return p4d;
Thanks, - Qing > >> } >> } >> zero_pud_populate(p4d, addr, next); >> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h >> index a61eeee3095a..033335c13b25 100644 >> --- a/mm/kasan/kasan.h >> +++ b/mm/kasan/kasan.h >> @@ -291,16 +291,22 @@ struct kasan_stack_ring { >> >> #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) >> >> +#ifndef __HAVE_ARCH_SHADOW_MAP >> static inline const void *kasan_shadow_to_mem(const void *shadow_addr) >> { >> return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET) >> << KASAN_SHADOW_SCALE_SHIFT); >> } >> +#endif >> >> static __always_inline bool addr_has_metadata(const void *addr) >> { >> +#ifdef __HAVE_ARCH_SHADOW_MAP >> + return (kasan_mem_to_shadow((void *)addr) != NULL); >> +#else >> return (kasan_reset_tag(addr) >= >> kasan_shadow_to_mem((void *)KASAN_SHADOW_START)); >> +#endif >> } >> >> /** >> -- >> 2.20.1 >>
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