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authorHailong Liu <liu.hailong6@zte.com.cn>2021-01-12 15:49:14 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-01-12 18:12:54 -0800
commit29970dc24faf0078beb4efab5455b4f504d2198d (patch)
treeebe8dcf7ced8b12e369b90183c0257401c12949c /mm/kasan
parent7ea510b92c7c9b4eb5ff72e6b4bbad4b0407a914 (diff)
arm/kasan: fix the array size of kasan_early_shadow_pte[]
The size of kasan_early_shadow_pte[] now is PTRS_PER_PTE which defined to 512 for arm. This means that it only covers the prev Linux pte entries, but not the HWTABLE pte entries for arm. The reason it currently works is that the symbol kasan_early_shadow_page immediately following kasan_early_shadow_pte in memory is page aligned, which makes kasan_early_shadow_pte look like a 4KB size array. But we can't ensure the order is always right with different compiler/linker, or if more bss symbols are introduced. We had a test with QEMU + vexpress:put a 512KB-size symbol with attribute __section(".bss..page_aligned") after kasan_early_shadow_pte, and poisoned it after kasan_early_init(). Then enabled CONFIG_KASAN, it failed to boot up. Link: https://lkml.kernel.org/r/20210109044622.8312-1-hailongliiu@yeah.net Signed-off-by: Hailong Liu <liu.hailong6@zte.com.cn> Signed-off-by: Ziliang Guo <guo.ziliang@zte.com.cn> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan')
-rw-r--r--mm/kasan/init.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/kasan/init.c b/mm/kasan/init.c
index bc0ad208b3a7..7ca0b92d5886 100644
--- a/mm/kasan/init.c
+++ b/mm/kasan/init.c
@@ -64,7 +64,8 @@ static inline bool kasan_pmd_table(pud_t pud)
return false;
}
#endif
-pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;
+pte_t kasan_early_shadow_pte[PTRS_PER_PTE + PTE_HWTABLE_PTRS]
+ __page_aligned_bss;
static inline bool kasan_pte_table(pmd_t pmd)
{