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authorChris Metcalf <cmetcalf@tilera.com>2012-05-11 00:01:44 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-11 02:06:44 +0400
commit4998a6c0edce7fae9c0a5463f6ec3fa585258ee7 (patch)
treed19a02785d8a5793abefb0ec3edb435c77e96a7e /mm/hugetlb.c
parent93278814d3590eba0ee360b8d69a35c7f2203ea8 (diff)
downloadlinux-4998a6c0edce7fae9c0a5463f6ec3fa585258ee7.tar.xz
hugetlb: prevent BUG_ON in hugetlb_fault() -> hugetlb_cow()
Commit 66aebce747eaf ("hugetlb: fix race condition in hugetlb_fault()") added code to avoid a race condition by elevating the page refcount in hugetlb_fault() while calling hugetlb_cow(). However, one code path in hugetlb_cow() includes an assertion that the page count is 1, whereas it may now also have the value 2 in this path. The consensus is that this BUG_ON has served its purpose, so rather than extending it to cover both cases, we just remove it. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Hillf Danton <dhillf@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@vger.kernel.org> [3.0.29+, 3.2.16+, 3.3.3+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5a16423a512c..ae8f708e3d75 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2498,7 +2498,6 @@ retry_avoidcopy:
if (outside_reserve) {
BUG_ON(huge_pte_none(pte));
if (unmap_ref_private(mm, vma, old_page, address)) {
- BUG_ON(page_count(old_page) != 1);
BUG_ON(huge_pte_none(pte));
spin_lock(&mm->page_table_lock);
ptep = huge_pte_offset(mm, address & huge_page_mask(h));