diff options
| author | Andrea Arcangeli <aarcange@redhat.com> | 2017-03-09 16:16:28 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-20 10:07:18 +0100 |
| commit | 275314e90c5e84c972be2da278cee60279e07fc7 (patch) | |
| tree | f6ac70d5a798c94e64eb1a48b3b575e07cf82263 /fs | |
| parent | 9bcd15bdfb6151e0418fa9321d4dce2b2eb0cb16 (diff) | |
userfaultfd: shmem: __do_fault requires VM_FAULT_NOPAGE
[ Upstream commit 6bbc4a4144b1a69743022ac68dfaf6e7d993abb9 ]
__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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -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 b86054cc41db..784d667475ae 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -419,7 +419,7 @@ int handle_userfault(struct fault_env *fe, unsigned long reason) * in such case. */ down_read(&mm->mmap_sem); - ret = 0; + ret = VM_FAULT_NOPAGE; } } |