cortex_m: dwt_num_comp should be set to zero in cortex_m_dwt_free()

A segmentation fault in cortex_m_endreset_event() is sometimes raised
with very broken target like Kinetis Kx with erased flash and active WDOG.
Debugging revealed that cortex_m->dwt_num_comp is 4 and
dwt_list is NULL at cortex_m:290

Change-Id: I229c59d6da13d816df513d1dbb19968e4b5951e2
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/2989
Reviewed-by: Thomas Schmid <thomas@rfranging.com>
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c
index b55de1bc6d67a450ef7594852c0fc9b031876f5d..88b226d85c8ad86e6167ad7a67a0fdb457b18b2f 100644 (file)
--- a/src/target/cortex_m.c
+++ b/src/target/cortex_m.c
@@ -1865,6 +1865,7 @@ static void cortex_m_dwt_free(struct target *target)
 
        free(cm->dwt_comparator_list);
        cm->dwt_comparator_list = NULL;
 
        free(cm->dwt_comparator_list);
        cm->dwt_comparator_list = NULL;

+       cm->dwt_num_comp = 0;

 
        if (cache) {
                register_unlink_cache(&target->reg_cache, cache);
 
        if (cache) {
                register_unlink_cache(&target->reg_cache, cache);