From 1f64d69c7ad2e48e697493e45590679f7a69b7b2 Mon Sep 17 00:00:00 2001
From: Dean Nelson <dnelson@redhat.com>
Date: Thu, 2 Dec 2010 14:31:12 -0800
Subject: [PATCH] mm/hugetlb.c: avoid double unlock_page() in hugetlb_fault()

Have hugetlb_fault() call unlock_page(page) only if it had previously
called lock_page(page).

Setting CONFIG_DEBUG_VM=y and then running the libhugetlbfs test suite,
resulted in the tripping of VM_BUG_ON(!PageLocked(page)) in
unlock_page() having been called by hugetlb_fault() when page ==
pagecache_page.  This patch remedied the problem.

Signed-off-by: Dean Nelson <dnelson@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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