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authorMichal Hocko <mhocko@suse.cz>2014-01-23 15:53:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-23 16:36:52 -0800
commitcc81717ed3bc6d4f3738d13a1e097437caada0e9 (patch)
tree8e103fa5bfea059f1ace38d205a09e42e19dd6db /mm/mempolicy.c
parent54b9dd14d09f24927285359a227aa363ce46089e (diff)
downloadop-kernel-dev-cc81717ed3bc6d4f3738d13a1e097437caada0e9.zip
op-kernel-dev-cc81717ed3bc6d4f3738d13a1e097437caada0e9.tar.gz
mm: new_vma_page() cannot see NULL vma for hugetlb pages
Commit 11c731e81bb0 ("mm/mempolicy: fix !vma in new_vma_page()") has removed BUG_ON(!vma) from new_vma_page which is partially correct because page_address_in_vma will return EFAULT for non-linear mappings and at least shared shmem might be mapped this way. The patch also tried to prevent NULL ptr for hugetlb pages which is not correct AFAICS because hugetlb pages cannot be mapped as VM_NONLINEAR and other conditions in page_address_in_vma seem to be legit and catch real bugs. This patch restores BUG_ON for PageHuge to catch potential issues when the to-be-migrated page is not setup properly. Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Bob Liu <bob.liu@oracle.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.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.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 947293e..463b7fb 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1199,10 +1199,8 @@ static struct page *new_vma_page(struct page *page, unsigned long private, int *
}
if (PageHuge(page)) {
- if (vma)
- return alloc_huge_page_noerr(vma, address, 1);
- else
- return NULL;
+ BUG_ON(!vma);
+ return alloc_huge_page_noerr(vma, address, 1);
}
/*
* if !vma, alloc_page_vma() will use task or system default policy
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