User processes trying to access an invalid memory address via PIO will receive a SIGBUS signal instead of causing a panic. Memory errors will receive a SIGKILL since a SIGBUS may result in a coredump which may attempt to repeat the faulting access. Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>