ALSA: dice: fix null pointer dereference when node is disconnected

BugLink: https://bugs.launchpad.net/bugs/1921712
commit dd7b836d6bc935df95c826f69ff4d051f5561604 upstream.

When node is removed from IEEE 1394 bus, any transaction fails to the node.
In the case, ALSA dice driver doesn't stop isochronous contexts even if
they are running. As a result, null pointer dereference occurs in callback
from the running context.

This commit fixes the bug to release isochronous contexts always.

Cc: <stable@vger.kernel.org> # v5.4 or later
Fixes: e9f21129b8d8 ("ALSA: dice: support AMDTP domain")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210312093407.23437-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

diff --git a/sound/firewire/dice/dice-stream.c b/sound/firewire/dice/dice-stream.c
index 8e0c0380b4c4bdf11389e7bc38d2b7d5df9a213a..1a14c083e8ceaac63488d37f367878323d5a7459 100644 (file)
--- a/sound/firewire/dice/dice-stream.c
+++ b/sound/firewire/dice/dice-stream.c
@@ -493,11 +493,10 @@ void snd_dice_stream_stop_duplex(struct snd_dice *dice)
        struct reg_params tx_params, rx_params;
 
        if (dice->substreams_counter == 0) {
-               if (get_register_params(dice, &tx_params, &rx_params) >= 0) {
-                       amdtp_domain_stop(&dice->domain);
+               if (get_register_params(dice, &tx_params, &rx_params) >= 0)
                        finish_session(dice, &tx_params, &rx_params);
-               }
 
+               amdtp_domain_stop(&dice->domain);
                release_resources(dice);
        }
 }