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authorChris Metcalf <cmetcalf@tilera.com>2012-05-10 13:01:44 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-21 09:40:02 -0700
commitafe85051b486d5d558d93ab2e509dc3bfdffc2c5 (patch)
tree55eb832f866f67c2fd86b7b97009c5d40f08a774 /mm/hugetlb.c
parent4f5e387650ca965426a7b4681120988b4ba0e116 (diff)
hugetlb: prevent BUG_ON in hugetlb_fault() -> hugetlb_cow()
commit 4998a6c0edce7fae9c0a5463f6ec3fa585258ee7 upstream. 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 f7001ac53b37..00b0abb75c94 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2398,7 +2398,6 @@ 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);
goto retry_avoidcopy;