[media] mantis: fix silly crash case

If we set mantis->fe to NULL on an error its not a good idea to then try
passing NULL to the unregister paths and oopsing really.

Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=16473

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/media/dvb/mantis/mantis_dvb.c b/drivers/media/dvb/mantis/mantis_dvb.c
index e5180e45d310..5d15c6b74d9b 100644
--- a/drivers/media/dvb/mantis/mantis_dvb.c
+++ b/drivers/media/dvb/mantis/mantis_dvb.c
@@ -248,8 +248,10 @@ int __devinit mantis_dvb_init(struct mantis_pci *mantis)
 err5:
         tasklet_kill(&mantis->tasklet);
         dvb_net_release(&mantis->dvbnet);
-        dvb_unregister_frontend(mantis->fe);
-        dvb_frontend_detach(mantis->fe);
+        if (mantis->fe) {
+                dvb_unregister_frontend(mantis->fe);
+                dvb_frontend_detach(mantis->fe);
+        }
 err4:
         mantis->demux.dmx.remove_frontend(&mantis->demux.dmx, &mantis->fe_mem);