Instead of open coding the sequence from force_sigsegv() just call
it. This also fixes a bug because we were modifying ka->sa.sa_handler
(which is a copy of sighand->action[]), whereas the intention of the
code was to modify sighand->action[] directly.
As the original code was working with a copy it had no effect on
signal delivery.
Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>