firewire: potentially invalid pointers used in fw_card_bm_work

The bus management workqueue job was in danger to dereference NULL
pointers.  Also, after having temporarily lifted card->lock, a few node
pointers and a device pointer may have become invalid.

Add NULL pointer checks and get the necessary references.  Also, move
card->local_node out of fw_card_bm_work's sight during shutdown of the
card.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/firewire/fw-topology.c b/drivers/firewire/fw-topology.c
index 172c1867e9a..e47bb040197 100644
--- a/drivers/firewire/fw-topology.c
+++ b/drivers/firewire/fw-topology.c
@@ -383,6 +383,7 @@ void fw_destroy_nodes(struct fw_card *card)
         card->color++;
         if (card->local_node != NULL)
                 for_each_fw_node(card, card->local_node, report_lost_node);
+        card->local_node = NULL;
         spin_unlock_irqrestore(&card->lock, flags);
 }