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>
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2 changed files with 35 additions and 6 deletions
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@ -161,7 +161,6 @@ config MEMORY_HOTPLUG
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bool "Allow for memory hot-add"
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depends on SPARSEMEM || X86_64_ACPI_NUMA
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depends on ARCH_ENABLE_MEMORY_HOTPLUG
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depends on COMPILE_TEST || !KASAN
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config MEMORY_HOTPLUG_SPARSE
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def_bool y
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@ -737,17 +737,47 @@ void __asan_unpoison_stack_memory(const void *addr, size_t size)
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EXPORT_SYMBOL(__asan_unpoison_stack_memory);
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#ifdef CONFIG_MEMORY_HOTPLUG
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static int kasan_mem_notifier(struct notifier_block *nb,
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static int __meminit kasan_mem_notifier(struct notifier_block *nb,
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unsigned long action, void *data)
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{
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return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
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struct memory_notify *mem_data = data;
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unsigned long nr_shadow_pages, start_kaddr, shadow_start;
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unsigned long shadow_end, shadow_size;
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nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
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start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
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shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
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shadow_size = nr_shadow_pages << PAGE_SHIFT;
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shadow_end = shadow_start + shadow_size;
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if (WARN_ON(mem_data->nr_pages % KASAN_SHADOW_SCALE_SIZE) ||
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WARN_ON(start_kaddr % (KASAN_SHADOW_SCALE_SIZE << PAGE_SHIFT)))
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return NOTIFY_BAD;
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switch (action) {
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case MEM_GOING_ONLINE: {
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void *ret;
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ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
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shadow_end, GFP_KERNEL,
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PAGE_KERNEL, VM_NO_GUARD,
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pfn_to_nid(mem_data->start_pfn),
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__builtin_return_address(0));
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if (!ret)
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return NOTIFY_BAD;
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kmemleak_ignore(ret);
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return NOTIFY_OK;
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}
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case MEM_OFFLINE:
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vfree((void *)shadow_start);
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}
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return NOTIFY_OK;
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}
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static int __init kasan_memhotplug_init(void)
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{
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pr_info("WARNING: KASAN doesn't support memory hot-add\n");
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pr_info("Memory hot-add will be disabled\n");
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hotplug_memory_notifier(kasan_mem_notifier, 0);
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return 0;
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