Messages in this thread Patch in this message | | | From | Liam Howlett <> | Subject | [PATCH] fs/userfaultfd: Fix vma iteration in mas_for_each() loop | Date | Wed, 15 Jun 2022 16:42:17 +0000 |
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The maple tree state becomes stale when the tree is altered and requires the iteration to be paused with mas_pause(). This forces the next iteration to start from the top of tree for the next entry.
Reported-by: syzbot+68771c0e74f7bb7804e5@syzkaller.appspotmail.com Fixes: d3ccd17e7c96 ("mm: start tracking VMAs with maple tree") Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> --- fs/userfaultfd.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index d18500633ebe..d398f6bf6d74 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -886,10 +886,13 @@ static int userfaultfd_release(struct inode *inode, struct file *file) vma->vm_file, vma->vm_pgoff, vma_policy(vma), NULL_VM_UFFD_CTX, anon_vma_name(vma)); - if (prev) + if (prev) { + mas_pause(&mas); vma = prev; - else + } else { prev = vma; + } + vma->vm_flags = new_flags; vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX; } -- 2.35.1
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