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authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>2016-07-26 15:24:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-26 16:19:19 -0700
commit337d9abf1cd1a59645d91b6d0b1685a476b81978 (patch)
treeaace71b1608dfbde1c4c35bd03cbdac60fe1f64a
parente3a2713c3cfa9c41fac57447533079d8da23319b (diff)
downloadlinux-337d9abf1cd1a59645d91b6d0b1685a476b81978.tar.bz2
mm: thp: check pmd_trans_unstable() after split_huge_pmd()
split_huge_pmd() doesn't guarantee that the pmd is normal pmd pointing to pte entries, which can be checked with pmd_trans_unstable(). Some callers make this assertion and some do it differently and some not, so let's do it in a unified manner. Link: http://lkml.kernel.org/r/1464741400-12143-1-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/gup.c2
-rw-r--r--mm/mempolicy.c2
-rw-r--r--mm/mprotect.c2
-rw-r--r--mm/mremap.c3
4 files changed, 6 insertions, 3 deletions
diff --git a/mm/gup.c b/mm/gup.c
index c057784c8444..dee142e100f4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -279,6 +279,8 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
spin_unlock(ptl);
ret = 0;
split_huge_pmd(vma, pmd, address);
+ if (pmd_trans_unstable(pmd))
+ ret = -EBUSY;
} else {
get_page(page);
spin_unlock(ptl);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 297d6854f849..fe90e5051012 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -512,6 +512,8 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
}
}
+ if (pmd_trans_unstable(pmd))
+ return 0;
retry:
pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE) {
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 5019a1ef2848..a4830f0325fe 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -163,7 +163,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
if (next - addr != HPAGE_PMD_SIZE) {
split_huge_pmd(vma, pmd, addr);
- if (pmd_none(*pmd))
+ if (pmd_trans_unstable(pmd))
continue;
} else {
int nr_ptes = change_huge_pmd(vma, pmd, addr,
diff --git a/mm/mremap.c b/mm/mremap.c
index 1f157adfdaf9..da22ad2a5678 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -210,9 +210,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
}
}
split_huge_pmd(vma, old_pmd, old_addr);
- if (pmd_none(*old_pmd))
+ if (pmd_trans_unstable(old_pmd))
continue;
- VM_BUG_ON(pmd_trans_huge(*old_pmd));
}
if (pte_alloc(new_vma->vm_mm, new_pmd, new_addr))
break;