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

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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>
This commit is contained in:
Naoya Horiguchi
2010-07-02 14:47:20 +09:00
committed by Andi Kleen
parent e3390f67a7
commit 28957a5467
1 changed files with 3 additions and 1 deletions
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4
mm/hugetlb.c
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@@ -2324,9 +2324,11 @@ retry_avoidcopy:
* and just make the page writable */ * and just make the page writable */
avoidcopy = (page_mapcount(old_page) == 1); avoidcopy = (page_mapcount(old_page) == 1);
if (avoidcopy) { if (avoidcopy) {
if (!trylock_page(old_page)) if (!trylock_page(old_page)) {
if (PageAnon(old_page)) if (PageAnon(old_page))
page_move_anon_rmap(old_page, vma, address); page_move_anon_rmap(old_page, vma, address);
} else
unlock_page(old_page);
set_huge_ptep_writable(vma, address, ptep); set_huge_ptep_writable(vma, address, ptep);
return 0; return 0;
} }