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author | Herbert Xu <herbert@gondor.apana.org.au> | 2017-03-24 16:58:58 +0300 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2017-03-24 16:58:58 +0300 |
commit | 2e6d603e5163e6f32a8686744b4d53e8778957ba (patch) | |
tree | ead238ea5efe7b3f52728793fe9dfa76ca52bc31 /mm/madvise.c | |
parent | 28845b079b9611b3082aa53e2dae2ea10a16a1c2 (diff) | |
parent | 97da3854c526d3a6ee05c849c96e48d21527606c (diff) | |
download | linux-2e6d603e5163e6f32a8686744b4d53e8778957ba.tar.xz |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux
Merging 4.11-rc3 to pick up md5 removal from /dev/random.
Diffstat (limited to 'mm/madvise.c')
-rw-r--r-- | mm/madvise.c | 44 |
1 files changed, 41 insertions, 3 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index dc5927c812d3..7a2abf0127ae 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -513,7 +513,43 @@ static long madvise_dontneed(struct vm_area_struct *vma, if (!can_madv_dontneed_vma(vma)) return -EINVAL; - userfaultfd_remove(vma, prev, start, end); + if (!userfaultfd_remove(vma, start, end)) { + *prev = NULL; /* mmap_sem has been dropped, prev is stale */ + + down_read(¤t->mm->mmap_sem); + vma = find_vma(current->mm, start); + if (!vma) + return -ENOMEM; + if (start < vma->vm_start) { + /* + * This "vma" under revalidation is the one + * with the lowest vma->vm_start where start + * is also < vma->vm_end. If start < + * vma->vm_start it means an hole materialized + * in the user address space within the + * virtual range passed to MADV_DONTNEED. + */ + return -ENOMEM; + } + if (!can_madv_dontneed_vma(vma)) + return -EINVAL; + if (end > vma->vm_end) { + /* + * Don't fail if end > vma->vm_end. If the old + * vma was splitted while the mmap_sem was + * released the effect of the concurrent + * operation may not cause MADV_DONTNEED to + * have an undefined result. There may be an + * adjacent next vma that we'll walk + * next. userfaultfd_remove() will generate an + * UFFD_EVENT_REMOVE repetition on the + * end-vma->vm_end range, but the manager can + * handle a repetition fine. + */ + end = vma->vm_end; + } + VM_WARN_ON(start >= end); + } zap_page_range(vma, start, end - start); return 0; } @@ -554,8 +590,10 @@ static long madvise_remove(struct vm_area_struct *vma, * mmap_sem. */ get_file(f); - userfaultfd_remove(vma, prev, start, end); - up_read(¤t->mm->mmap_sem); + if (userfaultfd_remove(vma, start, end)) { + /* mmap_sem was not released by userfaultfd_remove() */ + up_read(¤t->mm->mmap_sem); + } error = vfs_fallocate(f, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, offset, end - start); |