diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/mm/memory.c b/mm/memory.c index 5f5d1f039bf4..b03a4a21c1d0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -712,7 +712,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, add_taint(TAINT_BAD_PAGE); } -static inline int is_cow_mapping(vm_flags_t flags) +static inline bool is_cow_mapping(vm_flags_t flags) { return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; } @@ -1039,6 +1039,9 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, unsigned long next; unsigned long addr = vma->vm_start; unsigned long end = vma->vm_end; + unsigned long mmun_start; /* For mmu_notifiers */ + unsigned long mmun_end; /* For mmu_notifiers */ + bool is_cow; int ret; /* @@ -1072,8 +1075,12 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, * parent mm. And a permission downgrade will only happen if * is_cow_mapping() returns true. */ - if (is_cow_mapping(vma->vm_flags)) - mmu_notifier_invalidate_range_start(src_mm, addr, end); + is_cow = is_cow_mapping(vma->vm_flags); + mmun_start = addr; + mmun_end = end; + if (is_cow) + mmu_notifier_invalidate_range_start(src_mm, mmun_start, + mmun_end); ret = 0; dst_pgd = pgd_offset(dst_mm, addr); @@ -1089,9 +1096,8 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, } } while (dst_pgd++, src_pgd++, addr = next, addr != end); - if (is_cow_mapping(vma->vm_flags)) - mmu_notifier_invalidate_range_end(src_mm, - vma->vm_start, end); + if (is_cow) + mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end); return ret; } @@ -2516,7 +2522,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, spinlock_t *ptl, pte_t orig_pte) __releases(ptl) { - struct page *old_page, *new_page; + struct page *old_page, *new_page = NULL; pte_t entry; int ret = 0; int page_mkwrite = 0; @@ -2760,10 +2766,14 @@ gotten: } else mem_cgroup_uncharge_page(new_page); - if (new_page) - page_cache_release(new_page); unlock: pte_unmap_unlock(page_table, ptl); + if (new_page) { + if (new_page == old_page) + /* cow happened, notify before releasing old_page */ + mmu_notifier_invalidate_page(mm, address); + page_cache_release(new_page); + } if (old_page) { /* * Don't let another task, with possibly unlocked vma, |