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author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2014-07-23 14:00:19 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-07-23 15:10:55 -0700 |
commit | 0253d634e0803a8376a0d88efee0bf523d8673f9 (patch) | |
tree | adf2543a5c7149c6287d7f03ecca1bffcb6395b2 | |
parent | 4e66d445d0421a159135572a0ba44b75c7c4adfa (diff) | |
download | linux-0253d634e0803a8376a0d88efee0bf523d8673f9.tar.gz |
mm: hugetlb: fix copy_hugetlb_page_range()
Commit 4a705fef9862 ("hugetlb: fix copy_hugetlb_page_range() to handle migration/hwpoisoned entry") changed the order of huge_ptep_set_wrprotect() and huge_ptep_get(), which leads to breakage in some workloads like hugepage-backed heap allocation via libhugetlbfs. This patch fixes it. The test program for the problem is shown below: $ cat heap.c #include <unistd.h> #include <stdlib.h> #include <string.h> #define HPS 0x200000 int main() { int i; char *p = malloc(HPS); memset(p, '1', HPS); for (i = 0; i < 5; i++) { if (!fork()) { memset(p, '2', HPS); p = malloc(HPS); memset(p, '3', HPS); free(p); return 0; } } sleep(1); free(p); return 0; } $ export HUGETLB_MORECORE=yes ; export HUGETLB_NO_PREFAULT= ; hugectl --heap ./heap Fixes 4a705fef9862 ("hugetlb: fix copy_hugetlb_page_range() to handle migration/hwpoisoned entry"), so is applicable to -stable kernels which include it. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Guillaume Morin <guillaume@morinfr.org> Suggested-by: Guillaume Morin <guillaume@morinfr.org> Acked-by: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> [2.6.37+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | mm/hugetlb.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 2024bbd573d2..9221c02ed9e2 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2604,6 +2604,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, } else { if (cow) huge_ptep_set_wrprotect(src, addr, src_pte); + entry = huge_ptep_get(src_pte); ptepage = pte_page(entry); get_page(ptepage); page_dup_rmap(ptepage); |