torture: Don't kill gdb sessions

The rcutorture scripting will do a "kill -9" on any guest OS that exceeds
its --duration by more than a few minutes, which is very valuable when
bugs result in hangs.  However, this is a problem when the "hang" was due
to a --gdb debugging session.

This commit therefore refrains from killing the guest OS when a debugging
session is in progress.  This means that the user must manually kill the
kvm.sh process group if a hang really does occur.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh

@@ -206,7 +206,10 @@ do
 	kruntime=`gawk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
 	if test -z "$qemu_pid" || kill -0 "$qemu_pid" > /dev/null 2>&1
 	then
-		if test $kruntime -ge $seconds -o -f "$TORTURE_STOPFILE"
+		if test -n "$TORTURE_KCONFIG_GDB_ARG"
+		then
+			:
+		elif test $kruntime -ge $seconds || test -f "$TORTURE_STOPFILE"
 		then
 			break;
 		fi