diff options
| -rw-r--r-- | mm/gup.c | 2 | ||||
| -rw-r--r-- | mm/memory.c | 11 | ||||
| -rw-r--r-- | mm/rmap.c | 3 |
3 files changed, 13 insertions, 3 deletions
@@ -917,7 +917,7 @@ static int gup_pud_range(pgd_t *pgdp, unsigned long addr, unsigned long end, pudp = pud_offset(pgdp, addr); do { - pud_t pud = ACCESS_ONCE(*pudp); + pud_t pud = READ_ONCE(*pudp); next = pud_addr_end(addr, end); if (pud_none(pud)) diff --git a/mm/memory.c b/mm/memory.c index 3e503831e042..d86aa88902a0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3202,7 +3202,16 @@ static int handle_pte_fault(struct mm_struct *mm, pte_t entry; spinlock_t *ptl; - entry = ACCESS_ONCE(*pte); + /* + * some architectures can have larger ptes than wordsize, + * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and CONFIG_32BIT=y, + * so READ_ONCE or ACCESS_ONCE cannot guarantee atomic accesses. + * The code below just needs a consistent view for the ifs and + * we later double check anyway with the ptl lock held. So here + * a barrier will do. + */ + entry = *pte; + barrier(); if (!pte_present(entry)) { if (pte_none(entry)) { if (vma->vm_ops) { diff --git a/mm/rmap.c b/mm/rmap.c index 19886fb2f13a..1e542744e131 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -581,7 +581,8 @@ pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address) * without holding anon_vma lock for write. So when looking for a * genuine pmde (in which to find pte), test present and !THP together. */ - pmde = ACCESS_ONCE(*pmd); + pmde = *pmd; + barrier(); if (!pmd_present(pmde) || pmd_trans_huge(pmde)) pmd = NULL; out: |