Currently the initial value of order in dissolve_free_huge_page is 64 or 32, which leads to the following warning in static checker: mm/hugetlb.c:1203 dissolve_free_huge_pages() warn: potential right shift more than type allows '9,18,64' This is a potential risk of infinite loop, because 1 << order (== 0) is used in for-loop like this: for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) ... So this patch simply avoids the risk by initializing with UINT_MAX. Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage") Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> --- mm/hugetlb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 271e4432734c..804437505a84 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1188,7 +1188,7 @@ static void dissolve_free_huge_page(struct page *page) */ void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) { - unsigned int order = 8 * sizeof(void *); + unsigned int order = UINT_MAX; unsigned long pfn; struct hstate *h; @@ -1200,6 +1200,7 @@ void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) if (order > huge_page_order(h)) order = huge_page_order(h); VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order)); + VM_BUG_ON(order == UINT_MAX); for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) dissolve_free_huge_page(pfn_to_page(pfn)); } -- 2.1.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href