Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 211037)
+++ channels/chan_sip.c	(working copy)
@@ -2249,8 +2249,12 @@
 			 * the packet's retransid will be set to -1. The atomicity of the setting and checking
 			 * of the retransid to -1 is ensured since in both cases p's lock is held.
 			 */
-			AST_SCHED_DEL_SPINLOCK(sched, cur->retransid, &p->lock);
-			free(cur);
+			if (AST_SCHED_DEL_SPINLOCK(sched, cur->retransid, &p->lock)) {
+				cur->next = p->packets;
+				p->packets = cur;
+			} else {
+				free(cur);
+			}
 			break;
 		}
 	}