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 Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ 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 -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html