ALSA: compress_offload: use safe list iteration in snd_compr_task_seq()

The sequence function can call snd_compr_task_free_one(). Use
list_for_each_entry_safe_reverse() to make sure that the used
pointers are safe.

Link: https://lore.kernel.org/linux-sound/[e-mail]/
Fixes: 04177158cf98 ("ALSA: compress_offload: introduce accel operation mode")
Reported-by: Dan Carpenter <[e-mail]>
Cc: Vinod Koul <[e-mail]>
Signed-off-by: Jaroslav Kysela <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

sound/core/compress_offload.c

···
 static int snd_compr_task_seq(struct snd_compr_stream *stream, unsigned long arg,
 					snd_compr_seq_func_t fcn)
 {
-	struct snd_compr_task_runtime *task;
+	struct snd_compr_task_runtime *task, *temp;
 	__u64 seqno;
 	int retval;
 
···
 		return -EFAULT;
 	retval = 0;
 	if (seqno == 0) {
-		list_for_each_entry_reverse(task, &stream->runtime->tasks, list)
+		list_for_each_entry_safe_reverse(task, temp, &stream->runtime->tasks, list)
 			fcn(stream, task);
 	} else {
 		task = snd_compr_find_task(stream, seqno);