diff options
| author | Andrea Arcangeli <aarcange@redhat.com> | 2018-12-14 14:17:17 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-21 14:13:04 +0100 |
| commit | b99eaefb6850b38abdd8a2029bbfde08170ec6c9 (patch) | |
| tree | 3fd8ff53b36338f0ba3d7eeea7b00bb6f199d344 | |
| parent | 5f4610fe2ed4351b45c0d82b3246f18b886d26f9 (diff) | |
userfaultfd: check VM_MAYWRITE was set after verifying the uffd is registered
commit 01e881f5a1fca4677e82733061868c6d6ea05ca7 upstream.
Calling UFFDIO_UNREGISTER on virtual ranges not yet registered in uffd
could trigger an harmless false positive WARN_ON. Check the vma is
already registered before checking VM_MAYWRITE to shut off the false
positive warning.
Link: http://lkml.kernel.org/r/20181206212028.18726-2-aarcange@redhat.com
Cc: <stable@vger.kernel.org>
Fixes: 29ec90660d68 ("userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: syzbot+06c7092e7d71218a2c16@syzkaller.appspotmail.com
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/userfaultfd.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index f92e1f2fc846..5f10052d2671 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1567,7 +1567,6 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, cond_resched(); BUG_ON(!vma_can_userfault(vma)); - WARN_ON(!(vma->vm_flags & VM_MAYWRITE)); /* * Nothing to do: this vma is already registered into this @@ -1576,6 +1575,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, if (!vma->vm_userfaultfd_ctx.ctx) goto skip; + WARN_ON(!(vma->vm_flags & VM_MAYWRITE)); + if (vma->vm_start > start) start = vma->vm_start; vma_end = min(end, vma->vm_end); |