[PATCH 5.4 03/60] ALSA: dice: fix null pointer dereference when node is disconnected

[Greg Kroah-Hartman]

From: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx> # v5.4 or later
Fixes: e9f21129b8d8 ("ALSA: dice: support AMDTP domain")
Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210312093407.23437-1-o-takashi@xxxxxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 sound/firewire/dice/dice-stream.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/sound/firewire/dice/dice-stream.c
+++ b/sound/firewire/dice/dice-stream.c
@@ -489,11 +489,10 @@ void snd_dice_stream_stop_duplex(struct
 	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);
 	}
 }