diff options
| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2016-07-26 15:24:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-26 16:19:19 -0700 |
| commit | 337d9abf1cd1a59645d91b6d0b1685a476b81978 (patch) | |
| tree | aace71b1608dfbde1c4c35bd03cbdac60fe1f64a | |
| parent | e3a2713c3cfa9c41fac57447533079d8da23319b (diff) | |
| download | linux-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.c | 2 | ||||
| -rw-r--r-- | mm/mempolicy.c | 2 | ||||
| -rw-r--r-- | mm/mprotect.c | 2 | ||||
| -rw-r--r-- | mm/mremap.c | 3 |
4 files changed, 6 insertions, 3 deletions
@@ -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; |