diff options
| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2014-07-23 14:00:19 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-31 12:44:09 -0700 |
| commit | dd8fca578cc01b181dddd05eee521f6c62ec4ca3 (patch) | |
| tree | ca1453125418ac4235f5336ce65c9f071a77c7b9 | |
| parent | ae6cea4f9a49eda3ee02826d9578db66350f2ad5 (diff) | |
mm: hugetlb: fix copy_hugetlb_page_range()
commit 0253d634e0803a8376a0d88efee0bf523d8673f9 upstream.
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>
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>
| -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 a646f1598d58..002f08e3d61c 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2461,6 +2461,7 @@ 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); |