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Subject[PATCH v4] x86/mm/kasan: Teach KASAN about the cpu_entry_area
Date
From: Andy Lutomirski <luto@kernel.org>

The cpu_entry_area will contain stacks. Make sure that KASAN has
appropriate shadow mappings for them.

Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: kasan-dev@googlegroups.com
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
---
arch/x86/mm/kasan_init_64.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 99dfed6dfef8..9ec70d780f1f 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -277,6 +277,7 @@ void __init kasan_early_init(void)
void __init kasan_init(void)
{
int i;
+ void *shadow_cpu_entry_begin, *shadow_cpu_entry_end;

#ifdef CONFIG_KASAN_INLINE
register_die_notifier(&kasan_die_notifier);
@@ -329,8 +330,23 @@ void __init kasan_init(void)
(unsigned long)kasan_mem_to_shadow(_end),
early_pfn_to_nid(__pa(_stext)));

+ shadow_cpu_entry_begin = (void *)__fix_to_virt(FIX_CPU_ENTRY_AREA_BOTTOM);
+ shadow_cpu_entry_begin = kasan_mem_to_shadow(shadow_cpu_entry_begin);
+ shadow_cpu_entry_begin = (void *)round_down((unsigned long)shadow_cpu_entry_begin,
+ PAGE_SIZE);
+
+ shadow_cpu_entry_end = (void *)(__fix_to_virt(FIX_CPU_ENTRY_AREA_TOP) + PAGE_SIZE);
+ shadow_cpu_entry_end = kasan_mem_to_shadow(shadow_cpu_entry_end);
+ shadow_cpu_entry_end = (void *)round_up((unsigned long)shadow_cpu_entry_end,
+ PAGE_SIZE);
+
kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
- (void *)KASAN_SHADOW_END);
+ shadow_cpu_entry_begin);
+
+ kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin,
+ (unsigned long)shadow_cpu_entry_end, 0);
+
+ kasan_populate_zero_shadow(shadow_cpu_entry_end, (void *)KASAN_SHADOW_END);

load_cr3(init_top_pgt);
__flush_tlb_all();
--
2.13.6
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