mm/hotplug: verify hotplug memory range (27356f54) · Commits · 戴 / test

add_memory() and remove_memory() can only handle a memory range aligned with section. There are problems when an unaligned range is added and then deleted as follows: - add_memory() with an unaligned range succeeds, but __add_pages() called from add_memory() adds a whole section of pages even though a given memory range is less than the section size. - remove_memory() to the added unaligned range hits BUG_ON() in __remove_pages(). This patch changes add_memory() and remove_memory() to check if a given memory range is aligned with section at the beginning. As the result, add_memory() fails with -EINVAL when a given range is unaligned, and does not add such memory range. This prevents remove_memory() to be called with an unaligned range as well. Note that remove_memory() has to use BUG_ON() since this function cannot fail. [akpm@linux-foundation.org: avoid printk warnings] Signed-off-by:

Toshi Kani <toshi.kani@hp.com> Acked-by:

KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by:

Tang Chen <tangchen@cn.fujitsu.com> Reviewed-by:

Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/memory_hotplug.c

+23 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1070,6 +1070,23 @@ out:
	return ret;		return ret;
	}		}

			static int check_hotplug_memory_range(u64 start, u64 size)
			{
			u64 start_pfn = start >> PAGE_SHIFT;
			u64 nr_pages = size >> PAGE_SHIFT;

			/* Memory range must be aligned with section */
			if ((start_pfn & ~PAGE_SECTION_MASK) \|\|
			(nr_pages % PAGES_PER_SECTION) \|\| (!nr_pages)) {
			pr_err("Section-unaligned hotplug range: start 0x%llx, size 0x%llx\n",
			(unsigned long long)start,
			(unsigned long long)size);
			return -EINVAL;
			}

			return 0;
			}

	/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */		/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
	int __ref add_memory(int nid, u64 start, u64 size)		int __ref add_memory(int nid, u64 start, u64 size)
	{		{
	@@ -1079,6 +1096,10 @@ int __ref add_memory(int nid, u64 start, u64 size)
	struct resource *res;		struct resource *res;
	int ret;		int ret;

			ret = check_hotplug_memory_range(start, size);
			if (ret)
			return ret;

	lock_memory_hotplug();		lock_memory_hotplug();

	res = register_memory_resource(start, size);		res = register_memory_resource(start, size);
	@@ -1786,6 +1807,8 @@ void __ref remove_memory(int nid, u64 start, u64 size)
	{		{
	int ret;		int ret;

			BUG_ON(check_hotplug_memory_range(start, size));

	lock_memory_hotplug();		lock_memory_hotplug();

	/*		/*

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