Index: channels/chan_iax2.c
===================================================================
--- channels/chan_iax2.c	(revision 131970)
+++ channels/chan_iax2.c	(working copy)
@@ -1306,8 +1306,8 @@
 		}
 	}
 	if (!owner && iaxs[callno]) {
-		AST_SCHED_DEL(sched, iaxs[callno]->lagid);
-		AST_SCHED_DEL(sched, iaxs[callno]->pingid);
+		AST_SCHED_DEL_SPINLOCK(sched, iaxs[callno]->lagid, &iaxsl[callno]);
+		AST_SCHED_DEL_SPINLOCK(sched, iaxs[callno]->pingid, &iaxsl[callno]);
 		iaxs[callno] = NULL;
 	}
 
Index: include/asterisk/sched.h
===================================================================
--- include/asterisk/sched.h	(revision 131985)
+++ include/asterisk/sched.h	(working copy)
@@ -60,6 +60,22 @@
 		(_sched_res); \
 	})
 
+#define AST_SCHED_DEL_SPINLOCK(sched, id, lock) \
+	({ \
+		int _count = 0; \
+		int _sched_res = -1; \
+		while (id > -1 && (_sched_res = ast_sched_del(sched, id)) && ++_count < 10) { \
+			ast_mutex_unlock(lock); \
+			usleep(1); \
+			ast_mutex_lock(lock); \
+		} \
+		if (_count == 10 && option_debug > 2) { \
+			ast_log(LOG_DEBUG, "Unable to cancel schedule ID %d.\n", id); \
+		} \
+		id = -1; \
+		(_sched_res); \
+	})
+
 struct sched_context;
 
 /*! \brief New schedule context