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Diffstat (limited to 'arch/x86/mm/kasan_init_64.c')
-rw-r--r--arch/x86/mm/kasan_init_64.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index d470cf219a2d..1b1110fa0057 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -120,11 +120,22 @@ void __init kasan_init(void)
kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
(void *)KASAN_SHADOW_END);
- memset(kasan_zero_page, 0, PAGE_SIZE);
-
load_cr3(init_level4_pgt);
__flush_tlb_all();
- init_task.kasan_depth = 0;
+ /*
+ * kasan_zero_page has been used as early shadow memory, thus it may
+ * contain some garbage. Now we can clear and write protect it, since
+ * after the TLB flush no one should write to it.
+ */
+ memset(kasan_zero_page, 0, PAGE_SIZE);
+ for (i = 0; i < PTRS_PER_PTE; i++) {
+ pte_t pte = __pte(__pa(kasan_zero_page) | __PAGE_KERNEL_RO);
+ set_pte(&kasan_zero_pte[i], pte);
+ }
+ /* Flush TLBs again to be sure that write protection applied. */
+ __flush_tlb_all();
+
+ init_task.kasan_depth = 0;
pr_info("KernelAddressSanitizer initialized\n");
}