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| author | Michal Hocko <mhocko@suse.com> | 2018-01-31 16:21:03 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-01-31 17:18:40 -0800 |
| commit | 389c8178d0904f944887ccca2256ff9d79c12e8e (patch) | |
| tree | b4b089a0b4406d0215237ecc28f4f34c14958a70 /mm/mempolicy.c | |
| parent | ebd637235890a3fa6a6d4bb57522098f2f59c693 (diff) | |
| download | lwn-389c8178d0904f944887ccca2256ff9d79c12e8e.tar.gz lwn-389c8178d0904f944887ccca2256ff9d79c12e8e.zip | |
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 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 3 |
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; |