path: root/mm/mempolicy.c
diff options
authorMichal Hocko <mhocko@suse.com>2018-01-31 16:21:03 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-31 17:18:40 -0800
commit389c8178d0904f944887ccca2256ff9d79c12e8e (patch)
treeb4b089a0b4406d0215237ecc28f4f34c14958a70 /mm/mempolicy.c
parenthugetlb, mempolicy: fix the mbind hugetlb migration (diff)
hugetlb, mbind: fall back to default policy if vma is NULL
Dan Carpenter has noticed that mbind migration callback (new_page) can get a NULL vma pointer and choke on it inside alloc_huge_page_vma which relies on the VMA to get the hstate. We used to BUG_ON this case but the BUG_+ON has been removed recently by "hugetlb, mempolicy: fix the mbind hugetlb migration". The proper way to handle this is to get the hstate from the migrated page and rely on huge_node (resp. get_vma_policy) do the right thing with null VMA. We are currently falling back to the default mempolicy in that case which is in line what THP path is doing here. Link: http://lkml.kernel.org/r/20180110104712.GR1732@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.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>
Diffstat (limited to '')
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 96823fa07f38..d879f1d8a44a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1121,7 +1121,8 @@ static struct page *new_page(struct page *page, unsigned long start, int **x)
if (PageHuge(page)) {
- return alloc_huge_page_vma(vma, address);
+ return alloc_huge_page_vma(page_hstate(compound_head(page)),
+ vma, address);
} else if (thp_migration_supported() && PageTransHuge(page)) {
struct page *thp;