diff options
| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2015-12-11 13:40:24 -0800 |
|---|---|---|
| committer | Luis Henriques <luis.henriques@canonical.com> | 2016-01-18 22:27:30 +0000 |
| commit | 60d786c5ab45c381d26976804fea5c6581ac7d76 (patch) | |
| tree | 1be05e275c6b230c28f47d9f50661923e59cfbe1 /mm/hugetlb.c | |
| parent | 03dd7ad336102531531d92215cf34900744ad6e8 (diff) | |
| download | linux-stable-60d786c5ab45c381d26976804fea5c6581ac7d76.tar.gz linux-stable-60d786c5ab45c381d26976804fea5c6581ac7d76.tar.bz2 linux-stable-60d786c5ab45c381d26976804fea5c6581ac7d76.zip | |
mm: hugetlb: fix hugepage memory leak caused by wrong reserve count
commit a88c769548047b21f76fd71e04b6a3300ff17160 upstream.
When dequeue_huge_page_vma() in alloc_huge_page() fails, we fall back on
alloc_buddy_huge_page() to directly create a hugepage from the buddy
allocator.
In that case, however, if alloc_buddy_huge_page() succeeds we don't
decrement h->resv_huge_pages, which means that successful
hugetlb_fault() returns without releasing the reserve count. As a
result, subsequent hugetlb_fault() might fail despite that there are
still free hugepages.
This patch simply adds decrementing code on that code path.
I reproduced this problem when testing v4.3 kernel in the following situation:
- the test machine/VM is a NUMA system,
- hugepage overcommiting is enabled,
- most of hugepages are allocated and there's only one free hugepage
which is on node 0 (for example),
- another program, which calls set_mempolicy(MPOL_BIND) to bind itself to
node 1, tries to allocate a hugepage,
- the allocation should fail but the reserve count is still hold.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ luis: backported to 3.16:
- use 'chg' instead of 'gbl_chg'
- adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index f3111955b701..b247049b534a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1398,7 +1398,10 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, page = alloc_buddy_huge_page(h, NUMA_NO_NODE); if (!page) goto out_uncharge_cgroup; - + if (!avoid_reserve && vma_has_reserves(vma, chg)) { + SetPagePrivate(page); + h->resv_huge_pages--; + } spin_lock(&hugetlb_lock); list_move(&page->lru, &h->hugepage_activelist); /* Fall through */ |