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| author | Chris Metcalf <cmetcalf@tilera.com> | 2012-05-10 22:01:44 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-11 00:06:44 +0200 |
| commit | 4998a6c0edce7fae9c0a5463f6ec3fa585258ee7 (patch) | |
| tree | d19a02785d8a5793abefb0ec3edb435c77e96a7e /mm/hugetlb.c | |
| parent | mm: fix division by 0 in percpu_pagelist_fraction() (diff) | |
| download | linux-4998a6c0edce7fae9c0a5463f6ec3fa585258ee7.tar.xz linux-4998a6c0edce7fae9c0a5463f6ec3fa585258ee7.zip | |
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.c | 1 |
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)); |