app: scripts: Stop trace collection before stopping CMUX

When traces are collected with CMUX trace backend, trace process
needs to be stopped before stopping CMUX. If trace process is
not stopped, I/O activity on CMUUX'ed UART may cause ldattach
process to enter uninterruptible sleep state instead of
terminating correctly. When this happens, SUB serial device
cannot be recovered without rebooting the Linux system.

Signed-off-by: Matti Oksanen <matti.oksanen@nordicsemi.no>

Author: moksanen

app/scripts/sm_stop_ppp.sh

@@ -8,23 +8,22 @@ PIDFILE="/var/run/nrf91-modem.pid"
 PPP_PIDFILE="/var/run/ppp-nrf91.pid"
 TRACE_PID_FILE="/var/run/nrf91-modem-trace.pid"
 
+# Stop trace collection
+if [ -f $TRACE_PID_FILE ]; then
+        echo "Stopping trace collection..."
+        kill $(cat $TRACE_PID_FILE) 2>/dev/null || true
+        rm -f $TRACE_PID_FILE
+fi
+
 # Request PPPD to terminate
 if [ -f $PPP_PIDFILE ]; then
         echo "Stopping PPP link..."
         kill -SIGTERM $(head -1 <$PPP_PIDFILE)
 fi
 
-
 # Wait for Shutdown script to complete
 if [ -f $PIDFILE ]; then
         echo "Waiting for Shutdown script to complete..."
         timeout 12s tail --pid=$(head -1 <$PIDFILE) -f /dev/null \
         || echo "Timeout waiting for Shutdown script to stop"
 fi
-
-# Stop trace collection
-if [ -f $TRACE_PID_FILE ]; then
-        echo "Stopping trace collection..."
-        kill $(cat $TRACE_PID_FILE) 2>/dev/null || true
-        rm -f $TRACE_PID_FILE
-fi