Commit 28957a54 authored Jul 02, 2010 by Naoya Horiguchi Committed by Andi Kleen Aug 11, 2010

hugetlb: add missing unlock in avoidcopy path in hugetlb_cow()



This patch fixes possible deadlock in hugepage lock_page()
by adding missing unlock_page().

libhugetlbfs test will hit this bug when the next patch in this
patchset ("hugetlb, HWPOISON: move PG_HWPoison bit check") is applied.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

parent e3390f67

mm/hugetlb.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2324,9 +2324,11 @@ static int hugetlb_cow(struct mm_struct mm, struct vm_area_struct vma,
		* and just make the page writable */
		avoidcopy = (page_mapcount(old_page) == 1);
		if (avoidcopy) {
		if (!trylock_page(old_page))
		if (!trylock_page(old_page)) {
		if (PageAnon(old_page))
		page_move_anon_rmap(old_page, vma, address);
		} else
		unlock_page(old_page);
		set_huge_ptep_writable(vma, address, ptep);
		return 0;
		}