audiod get_play_time_slot_num(): Avoid possible NULL pointer dereference.

The pointer to the buffer tree node is dereferenced unconditionally
in btr_get_node_start(). This patch makes sure we never pass a NULL
pointer to this function.

diff --git a/audiod_command.c b/audiod_command.c
index 05059ac..a0d0229 100644 (file)
--- a/audiod_command.c
+++ b/audiod_command.c
@@ -198,7 +198,7 @@ static int get_play_time_slot_num(void)
        FOR_EACH_SLOT(i) {
                struct slot_info *s = &slot[i];
                struct timeval wstime;
-               if (!s->wns)
+               if (!s->wns || !s->wns[0].btrn)
                        continue;
                btr_get_node_start(s->wns[0].btrn, &wstime);
                if (oldest_slot >= 0 && tv_diff(&wstime, &oldest_wstime, NULL) > 0)