firewire: net: fix use after free

Commit 8408dc1c14c1 "firewire: net: use dev_printk API" introduced a
use-after-free in a failure path.  fwnet_transmit_packet_failed(ptask)
may free ptask, then the dev_err() call dereferenced it.  The fix is
straightforward; simply reorder the two calls.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@vger.kernel.org # v3.4+
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c
index 6b895986dc22..4af0a7bad7f2 100644
--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -929,8 +929,6 @@ static void fwnet_write_complete(struct fw_card *card, int rcode,
         if (rcode == RCODE_COMPLETE) {
                 fwnet_transmit_packet_done(ptask);
         } else {
-                fwnet_transmit_packet_failed(ptask);
-
                 if (printk_timed_ratelimit(&j,  1000) || rcode != last_rcode) {
                         dev_err(&ptask->dev->netdev->dev,
                                 "fwnet_write_complete failed: %x (skipped %d)\n",
@@ -938,8 +936,10 @@ static void fwnet_write_complete(struct fw_card *card, int rcode,
 
                         errors_skipped = 0;
                         last_rcode = rcode;
-                } else
+                } else {
                         errors_skipped++;
+                }
+                fwnet_transmit_packet_failed(ptask);
         }
 }