From f92e44c5399d8914aad58bd2c74005b3640c5a9d Mon Sep 17 00:00:00 2001
From: Harald Welte <laforge@gnumonks.org>
Date: Mon, 1 Aug 2016 00:24:19 +0200
Subject: [PATCH] lapd_core: Fix crash in lapd_dl_flush_hist()

When lapd_dl_flush_hist() was called before we actually had started a
transmit history from lapd_dl_init(), we woul segfault before this
patch.

Change-Id: Ifa677c9b335dd2884b4f3e44699d901957a0500b
---
 src/gsm/lapd_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/gsm/lapd_core.c b/src/gsm/lapd_core.c
index fd1e70979..fd163c831 100644
--- a/src/gsm/lapd_core.c
+++ b/src/gsm/lapd_core.c
@@ -158,7 +158,7 @@ static void lapd_dl_flush_hist(struct lapd_datalink *dl)
 {
 	unsigned int i;
 
-	if (!dl->range_hist)
+	if (!dl->range_hist || !dl->tx_hist)
 		return;
 
 	for (i = 0; i < dl->range_hist; i++) {