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| author | Andrey Ryabinin <aryabinin@virtuozzo.com> | 2017-07-10 15:50:34 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-10 16:32:33 -0700 |
| commit | fa69b5989bb0031efa96f2f4ff49caf6532a0970 (patch) | |
| tree | b63559b6b8ca3e2f2645e06959f65970ad727461 /mm | |
| parent | 3f9ec80f7b22ec46272a32408c5cd91ae2f8c4c0 (diff) | |
| download | linux-fa69b5989bb0031efa96f2f4ff49caf6532a0970.tar.bz2 | |
mm/kasan: add support for memory hotplug
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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/Kconfig | 1 | ||||
| -rw-r--r-- | mm/kasan/kasan.c | 40 |
2 files changed, 35 insertions, 6 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index 46ef77d5c332..48b1af447fa7 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -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 diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 212bc62041de..509974a1911e 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -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; |