Subject: + mm-hotplug-verify-hotplug-memory-range.patch added to -mm tree
To: toshi.kani@xxxxxx,kosaki.motohiro@xxxxxxxxxxxxxx,liwanp@xxxxxxxxxxxxxxxxxx,tangchen@xxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 14 Aug 2013 15:09:20 -0700
The patch titled
Subject: mm/hotplug: verify hotplug memory range
has been added to the -mm tree. Its filename is
mm-hotplug-verify-hotplug-memory-range.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hotplug-verify-hotplug-memory-range.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hotplug-verify-hotplug-memory-range.patch
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------------------------------------------------------
From: Toshi Kani <toshi.kani@xxxxxx>
Subject: mm/hotplug: verify hotplug memory range
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.
Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reviewed-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Reviewed-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff -puN mm/memory_hotplug.c~mm-hotplug-verify-hotplug-memory-range mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-hotplug-verify-hotplug-memory-range
+++ a/mm/memory_hotplug.c
@@ -1070,6 +1070,22 @@ out:
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",
+ start, size);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
int __ref add_memory(int nid, u64 start, u64 size)
{
@@ -1079,6 +1095,10 @@ int __ref add_memory(int nid, u64 start,
struct resource *res;
int ret;
+ ret = check_hotplug_memory_range(start, size);
+ if (ret)
+ return ret;
+
lock_memory_hotplug();
res = register_memory_resource(start, size);
@@ -1786,6 +1806,8 @@ void __ref remove_memory(int nid, u64 st
{
int ret;
+ BUG_ON(check_hotplug_memory_range(start, size));
+
lock_memory_hotplug();
/*
_
Patches currently in -mm which might be from toshi.kani@xxxxxx are
mm-hotplug-remove-unnecessary-bug_on-in-__offline_pages.patch
mm-hotplug-verify-hotplug-memory-range.patch
linux-next.patch
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