diff --git a/channels/sig_pri.c b/channels/sig_pri.c
index 2a0c8eff528068d060f94ce24a5ebcb6b54c926e..e7b059fa7de30b962aecebcd17c9fa3f3cf9c33c 100644
--- a/channels/sig_pri.c
+++ b/channels/sig_pri.c
@@ -1510,6 +1510,7 @@ static void *pri_ss_thread(void *data)
 		ast_copy_string(chan->exten, exten, sizeof(chan->exten));
 		sig_pri_dsp_reset_and_flush_digits(p);
 		if (p->pri->overlapdial & DAHDI_OVERLAPDIAL_INCOMING) {
+			sig_pri_lock_private(p);
 			if (p->pri->pri) {		
 				if (!pri_grab(p, p->pri)) {
 					pri_proceeding(p->pri->pri, p->call, PVT_TO_CHANNEL(p), 0);
@@ -1519,6 +1520,7 @@ static void *pri_ss_thread(void *data)
 					ast_log(LOG_WARNING, "Unable to grab PRI on span %d\n", p->pri->span);
 				}
 			}
+			sig_pri_unlock_private(p);
 		}
 
 		sig_pri_set_echocanceller(p, 1);