From 1c32fc05b672d318578efda59371d4a426185c51 Mon Sep 17 00:00:00 2001
From: Jerry Jacobs <jerry.jacobs@dualinventive.com>
Date: Thu, 7 Apr 2016 12:08:05 +0200
Subject: [PATCH] st-probe: Fix segfault when programmer is already busy and
 null pointers are in the list

---
 src/st-probe.c      | 3 +++
 src/stlink-common.c | 2 ++
 src/stlink-usb.c    | 3 +++
 3 files changed, 8 insertions(+)

diff --git a/src/st-probe.c b/src/st-probe.c
index f5cf3d829..b58bb7ad6 100644
--- a/src/st-probe.c
+++ b/src/st-probe.c
@@ -8,6 +8,9 @@ void stlink_print_info(stlink_t *sl)
 {
 	const chip_params_t *params = NULL;
 
+	if (!sl)
+		return;
+
 	for (size_t n = 0; n < sizeof(sl->serial); n++)
 		printf("%02x", sl->serial[n]);
 	printf("\n");
diff --git a/src/stlink-common.c b/src/stlink-common.c
index 3a6e260d1..18c76fb86 100644
--- a/src/stlink-common.c
+++ b/src/stlink-common.c
@@ -481,6 +481,8 @@ static inline void write_flash_cr_bker_pnb(stlink_t *sl, uint32_t n) {
 
 void stlink_close(stlink_t *sl) {
     DLOG("*** stlink_close ***\n");
+    if (!sl)
+         return;
     sl->backend->close(sl);
     free(sl);
 }
diff --git a/src/stlink-usb.c b/src/stlink-usb.c
index ab555785c..8fed467ba 100644
--- a/src/stlink-usb.c
+++ b/src/stlink-usb.c
@@ -15,6 +15,9 @@
 enum SCSI_Generic_Direction {SG_DXFER_TO_DEV=0, SG_DXFER_FROM_DEV=0x80};
 
 void _stlink_usb_close(stlink_t* sl) {
+    if (!sl)
+        return;
+
     struct stlink_libusb * const handle = sl->backend_data;
     // maybe we couldn't even get the usb device?
     if (handle != NULL) {