From: Andrey Ryabinin <aryabinin@virtuozzo.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Potapenko <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, <kasan-dev@googlegroups.com>, <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>, Andrey Ryabinin <aryabinin@virtuozzo.com> Subject: [PATCH 4/4] mm/kasan: Add support for memory hotplug Date: Thu, 1 Jun 2017 19:23:38 +0300 [thread overview] Message-ID: <20170601162338.23540-4-aryabinin@virtuozzo.com> (raw) In-Reply-To: <20170601162338.23540-1-aryabinin@virtuozzo.com> 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. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> --- mm/Kconfig | 1 - mm/kasan/kasan.c | 40 +++++++++++++++++++++++++++++++++++----- 2 files changed, 35 insertions(+), 6 deletions(-) diff --git a/mm/Kconfig b/mm/Kconfig index f1fbde17d45d..c8df94059974 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 e6fe07a98677..ca11bc4ce205 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; -- 2.13.0
WARNING: multiple messages have this Message-ID (diff)
From: Andrey Ryabinin <aryabinin@virtuozzo.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Potapenko <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Ryabinin <aryabinin@virtuozzo.com> Subject: [PATCH 4/4] mm/kasan: Add support for memory hotplug Date: Thu, 1 Jun 2017 19:23:38 +0300 [thread overview] Message-ID: <20170601162338.23540-4-aryabinin@virtuozzo.com> (raw) In-Reply-To: <20170601162338.23540-1-aryabinin@virtuozzo.com> 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. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> --- mm/Kconfig | 1 - mm/kasan/kasan.c | 40 +++++++++++++++++++++++++++++++++++----- 2 files changed, 35 insertions(+), 6 deletions(-) diff --git a/mm/Kconfig b/mm/Kconfig index f1fbde17d45d..c8df94059974 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 e6fe07a98677..ca11bc4ce205 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; -- 2.13.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-06-01 16:22 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-06-01 16:23 [PATCH 1/4] mm/kasan: get rid of speculative shadow checks Andrey Ryabinin 2017-06-01 16:23 ` Andrey Ryabinin 2017-06-01 16:23 ` [PATCH 2/4] x86/kasan: don't allocate extra shadow memory Andrey Ryabinin 2017-06-01 16:23 ` Andrey Ryabinin 2017-06-01 16:23 ` [PATCH 3/4] arm64/kasan: " Andrey Ryabinin 2017-06-01 16:23 ` Andrey Ryabinin 2017-06-01 16:23 ` Andrey Ryabinin 2017-06-01 16:34 ` Mark Rutland 2017-06-01 16:34 ` Mark Rutland 2017-06-01 16:34 ` Mark Rutland 2017-06-01 16:45 ` Dmitry Vyukov 2017-06-01 16:45 ` Dmitry Vyukov 2017-06-01 16:45 ` Dmitry Vyukov 2017-06-01 16:52 ` Mark Rutland 2017-06-01 16:52 ` Mark Rutland 2017-06-01 16:52 ` Mark Rutland 2017-06-01 16:59 ` Andrey Ryabinin 2017-06-01 16:59 ` Andrey Ryabinin 2017-06-01 16:59 ` Andrey Ryabinin 2017-06-01 17:00 ` Andrey Ryabinin 2017-06-01 17:00 ` Andrey Ryabinin 2017-06-01 17:00 ` Andrey Ryabinin 2017-06-01 17:05 ` Dmitry Vyukov 2017-06-01 17:05 ` Dmitry Vyukov 2017-06-01 17:05 ` Dmitry Vyukov 2017-06-01 17:38 ` Dmitry Vyukov 2017-06-01 17:38 ` Dmitry Vyukov 2017-06-01 17:38 ` Dmitry Vyukov 2017-06-01 16:23 ` Andrey Ryabinin [this message] 2017-06-01 16:23 ` [PATCH 4/4] mm/kasan: Add support for memory hotplug Andrey Ryabinin 2017-06-01 17:45 ` [PATCH 1/4] mm/kasan: get rid of speculative shadow checks Dmitry Vyukov 2017-06-01 17:45 ` Dmitry Vyukov
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