[mm] b1f0502d04: INFO:trying_to_register_non-static_key

[David Rientjes]

On Wed, 21 Mar 2018, Laurent Dufour wrote:

> I found the root cause of this lockdep warning.
> 
> In mmap_region(), unmap_region() may be called while vma_link() has not been
> called. This happens during the error path if call_mmap() failed.
> 
> The only to fix that particular case is to call
> seqcount_init(&vma->vm_sequence) when initializing the vma in mmap_region().
> 

Ack, although that would require a fixup to dup_mmap() as well.