diff options
Diffstat (limited to 'mm/page_vma_mapped.c')
| -rw-r--r-- | mm/page_vma_mapped.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 2cf01d933f13..5b559967410e 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -212,6 +212,17 @@ restart: pvmw->ptl = NULL; } } else if (!pmd_present(pmde)) { + /* + * If PVMW_SYNC, take and drop THP pmd lock so that we + * cannot return prematurely, while zap_huge_pmd() has + * cleared *pmd but not decremented compound_mapcount(). + */ + if ((pvmw->flags & PVMW_SYNC) && + PageTransCompound(pvmw->page)) { + spinlock_t *ptl = pmd_lock(mm, pvmw->pmd); + + spin_unlock(ptl); + } return false; } if (!map_pte(pvmw)) |