diff --git a/main/sched.c b/main/sched.c
index 71b1c30723..f5f768eb98 100644
--- a/main/sched.c
+++ b/main/sched.c
@@ -118,6 +118,7 @@ struct ast_sched_context {
 	struct sched_thread *sched_thread;
 	/*! The scheduled task that is currently executing */
 	struct sched *currently_executing;
+	pthread_t currently_executing_on_thread_id;
 
 #ifdef SCHED_MAX_CACHE
 	AST_LIST_HEAD_NOLOCK(, sched) schedc;   /*!< Cache of unused schedule structures and how many */
@@ -626,6 +627,18 @@ int ast_sched_del(struct ast_sched_context *con, int id)
 			ast_log(LOG_WARNING,"sched entry %d not in the sched heap?\n", s->sched_id->id);
 		}
 		sched_release(con, s);
+	} else if (con->currently_executing_on_thread_id == pthread_self()) {
+		/* We might trample on deleted memory at this point. Not good,
+		 * but it's better than a deadlock.
+		 * Thou shalt not reschedule things from a scheduled callback!
+		 */
+		ast_log(LOG_ERROR,
+			"BUG! Trying to delete sched %d from the same callback %p (sched %d). "
+			"Ignoring so we don't deadlock\n",
+			id, con->currently_executing->callback, con->currently_executing->sched_id->id);
+		ast_log_backtrace();
+		/* We'll return -1 below, because s is NULL. The caller
+		 * will rightly assume that the unscheduling failed. */
 	} else if (con->currently_executing && (id == con->currently_executing->sched_id->id)) {
 		s = con->currently_executing;
 		s->deleted = 1;
@@ -771,10 +784,12 @@ int ast_sched_runq(struct ast_sched_context *con)
 		 */
 
 		con->currently_executing = current;
+		con->currently_executing_on_thread_id = pthread_self();
 		ast_mutex_unlock(&con->lock);
 		res = current->callback(current->data);
 		ast_mutex_lock(&con->lock);
 		con->currently_executing = NULL;
+		con->currently_executing_on_thread_id = 0;
 		ast_cond_signal(&current->cond);
 
 		if (res && !current->deleted) {