diff options
| author | Andrea Arcangeli | 2017-03-09 16:16:28 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2017-03-09 17:01:09 -0800 |
| commit | 6bbc4a4144b1a69743022ac68dfaf6e7d993abb9 (patch) | |
| tree | 6a9eaa82d3bb88a8de32ee18320559491fea8780 | |
| parent | ea6200e84182989a3cce9687cf79a23ac44ec4db (diff) | |
userfaultfd: shmem: __do_fault requires VM_FAULT_NOPAGE
__do_fault assumes vmf->page has been initialized and is valid if
VM_FAULT_NOPAGE is not returned by vma->vm_ops->fault(vma, vmf).
handle_userfault() in turn should return VM_FAULT_NOPAGE if it doesn't
return VM_FAULT_SIGBUS or VM_FAULT_RETRY (the other two possibilities).
This VM_FAULT_NOPAGE case is only invoked when signal are pending and it
didn't matter for anonymous memory before. It only started to matter
since shmem was introduced. hugetlbfs also takes a different path and
doesn't exercise __do_fault.
Link: http://lkml.kernel.org/r/20170228154201.GH5816@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/userfaultfd.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 973607df579d..f62199b90fd0 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -490,7 +490,7 @@ int handle_userfault(struct vm_fault *vmf, unsigned long reason) * in such case. */ down_read(&mm->mmap_sem); - ret = 0; + ret = VM_FAULT_NOPAGE; } } |