On 07/10/14 00:26, Dave Hansen wrote:
> On 07/09/2014 04:29 AM, Andrey Ryabinin wrote:
>> Address sanitizer dedicates 1/8 of the low memory to the shadow memory and uses direct
>> mapping with a scale and offset to translate a memory address to its corresponding
>> shadow address.
>>
>> Here is function to translate address to corresponding shadow address:
>>
>> unsigned long kasan_mem_to_shadow(unsigned long addr)
>> {
>> return ((addr - PAGE_OFFSET) >> KASAN_SHADOW_SCALE_SHIFT)
>> + kasan_shadow_start;
>> }
>
> How does this interact with vmalloc() addresses or those from a kmap()?
>
It's used only for lowmem:
static inline bool addr_is_in_mem(unsigned long addr)
{
return likely(addr >= PAGE_OFFSET && addr < (unsigned long)high_memory);
}
static __always_inline void check_memory_region(unsigned long addr,
size_t size, bool write)
{
....
if (!addr_is_in_mem(addr))
return;
// check shadow here
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