diff options
| author | Mike Rapoport <rppt@linux.vnet.ibm.com> | 2017-08-02 13:32:15 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-08-02 17:16:12 -0700 |
| commit | 9d95aa4bada24be35bb94827a55e1d6e243d866e (patch) | |
| tree | 89fc20ba88a75c6da517d88d1f7c9450ac0002e9 /fs/userfaultfd.c | |
| parent | 167d0f258fedbfc859ad4105b1ea236818d41bdd (diff) | |
| download | lwn-9d95aa4bada24be35bb94827a55e1d6e243d866e.tar.gz lwn-9d95aa4bada24be35bb94827a55e1d6e243d866e.zip | |
userfaultfd_zeropage: return -ENOSPC in case mm has gone
In the non-cooperative userfaultfd case, the process exit may race with
outstanding mcopy_atomic called by the uffd monitor. Returning -ENOSPC
instead of -EINVAL when mm is already gone will allow uffd monitor to
distinguish this case from other error conditions.
Unfortunately I overlooked userfaultfd_zeropage when updating
userfaultd_copy().
Link: http://lkml.kernel.org/r/1501136819-21857-1-git-send-email-rppt@linux.vnet.ibm.com
Fixes: 96333187ab162 ("userfaultfd_copy: return -ENOSPC in case mm has gone")
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/userfaultfd.c')
| -rw-r--r-- | fs/userfaultfd.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index cadcd12a3d35..2d8c2d848668 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1643,6 +1643,8 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx, ret = mfill_zeropage(ctx->mm, uffdio_zeropage.range.start, uffdio_zeropage.range.len); mmput(ctx->mm); + } else { + return -ENOSPC; } if (unlikely(put_user(ret, &user_uffdio_zeropage->zeropage))) return -EFAULT; |