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mm/kasan: add support for memory hotplug

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KASAN doesn't happen work with memory hotplug because hotplugged memory
doesn't have any shadow memory.  So any access to hotplugged memory
would cause a crash on shadow check.

Use memory hotplug notifier to allocate and map shadow memory when the
hotplugged memory is going online and free shadow after the memory
offlined.

Link: http://lkml.kernel.org/r/20170601162338.23540-4-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Ryabinin 2017-07-10 15:50:34 -07:00 • committed by Linus Torvalds
parent 3f9ec80f7b
commit fa69b5989b
2 changed files with 35 additions and 6 deletions
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1
mm/Kconfig
View file

@ -161,7 +161,6 @@ config MEMORY_HOTPLUG
bool "Allow for memory hot-add"
depends on SPARSEMEM || X86_64_ACPI_NUMA
depends on ARCH_ENABLE_MEMORY_HOTPLUG
depends on COMPILE_TEST || !KASAN
config MEMORY_HOTPLUG_SPARSE
def_bool y

40
mm/kasan/kasan.c
View file

@ -737,17 +737,47 @@ void __asan_unpoison_stack_memory(const void *addr, size_t size)
EXPORT_SYMBOL(__asan_unpoison_stack_memory);
#ifdef CONFIG_MEMORY_HOTPLUG
static int kasan_mem_notifier(struct notifier_block *nb,
static int __meminit kasan_mem_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
struct memory_notify *mem_data = data;
unsigned long nr_shadow_pages, start_kaddr, shadow_start;
unsigned long shadow_end, shadow_size;
nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
shadow_size = nr_shadow_pages << PAGE_SHIFT;
shadow_end = shadow_start + shadow_size;
if (WARN_ON(mem_data->nr_pages % KASAN_SHADOW_SCALE_SIZE) ||
WARN_ON(start_kaddr % (KASAN_SHADOW_SCALE_SIZE << PAGE_SHIFT)))
return NOTIFY_BAD;
switch (action) {
case MEM_GOING_ONLINE: {
void *ret;
ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
shadow_end, GFP_KERNEL,
PAGE_KERNEL, VM_NO_GUARD,
pfn_to_nid(mem_data->start_pfn),
__builtin_return_address(0));
if (!ret)
return NOTIFY_BAD;
kmemleak_ignore(ret);
return NOTIFY_OK;
}
case MEM_OFFLINE:
vfree((void *)shadow_start);
}
return NOTIFY_OK;
}
static int __init kasan_memhotplug_init(void)
{
pr_info("WARNING: KASAN doesn't support memory hot-add\n");
pr_info("Memory hot-add will be disabled\n");
hotplug_memory_notifier(kasan_mem_notifier, 0);
return 0;