diff --git a/tools/testing/selftests/net/fib_tests.sh b/tools/testing/selftests/net/fib_tests.sh
index b3ecccbbfcd20c..38e786aad67890 100755
--- a/tools/testing/selftests/net/fib_tests.sh
+++ b/tools/testing/selftests/net/fib_tests.sh
@@ -743,6 +743,16 @@ fib_notify_test()
 	cleanup &> /dev/null
 }
 
+# Create a new dummy_10 to remove all associated routes.
+reset_dummy_10()
+{
+	$IP link del dev dummy_10
+
+	$IP link add dummy_10 type dummy
+	$IP link set dev dummy_10 up
+	$IP -6 address add 2001:10::1/64 dev dummy_10
+}
+
 fib6_gc_test()
 {
 	setup
@@ -751,7 +761,7 @@ fib6_gc_test()
 	echo "Fib6 garbage collection test"
 	set -e
 
-	EXPIRE=3
+	EXPIRE=5
 
 	# Check expiration of routes every $EXPIRE seconds (GC)
 	$NS_EXEC sysctl -wq net.ipv6.route.gc_interval=$EXPIRE
@@ -763,44 +773,165 @@ fib6_gc_test()
 	$NS_EXEC sysctl -wq net.ipv6.route.flush=1
 
 	# Temporary routes
-	for i in $(seq 1 1000); do
+	for i in $(seq 1 5); do
 	    # Expire route after $EXPIRE seconds
 	    $IP -6 route add 2001:20::$i \
 		via 2001:10::2 dev dummy_10 expires $EXPIRE
 	done
-	sleep $(($EXPIRE * 2))
-	N_EXP_SLEEP=$($IP -6 route list |grep expires|wc -l)
-	if [ $N_EXP_SLEEP -ne 0 ]; then
-	    echo "FAIL: expected 0 routes with expires, got $N_EXP_SLEEP"
+	sleep $(($EXPIRE * 2 + 1))
+	N_EXP=$($IP -6 route list |grep expires|wc -l)
+	if [ $N_EXP -ne 0 ]; then
+	    echo "FAIL: expected 0 routes with expires, got $N_EXP"
 	    ret=1
 	else
 	    ret=0
 	fi
 
+	log_test $ret 0 "ipv6 route garbage collection"
+
+	reset_dummy_10
+
 	# Permanent routes
-	for i in $(seq 1 5000); do
+	for i in $(seq 1 5); do
 	    $IP -6 route add 2001:30::$i \
 		via 2001:10::2 dev dummy_10
 	done
 	# Temporary routes
-	for i in $(seq 1 1000); do
+	for i in $(seq 1 5); do
 	    # Expire route after $EXPIRE seconds
 	    $IP -6 route add 2001:20::$i \
 		via 2001:10::2 dev dummy_10 expires $EXPIRE
 	done
-	sleep $(($EXPIRE * 2))
-	N_EXP_SLEEP=$($IP -6 route list |grep expires|wc -l)
-	if [ $N_EXP_SLEEP -ne 0 ]; then
-	    echo "FAIL: expected 0 routes with expires," \
-		 "got $N_EXP_SLEEP (5000 permanent routes)"
+	sleep $(($EXPIRE * 2 + 1))
+	N_EXP=$($IP -6 route list |grep expires|wc -l)
+	if [ $N_EXP -ne 0 ]; then
+	    echo "FAIL: expected 0 routes with expires, got $N_EXP"
 	    ret=1
 	else
 	    ret=0
 	fi
 
-	set +e
+	log_test $ret 0 "ipv6 route garbage collection (with permanent routes)"
 
-	log_test $ret 0 "ipv6 route garbage collection"
+	reset_dummy_10
+
+	# Permanent routes
+	for i in $(seq 1 5); do
+	    $IP -6 route add 2001:20::$i \
+		via 2001:10::2 dev dummy_10
+	done
+	# Replace with temporary routes
+	for i in $(seq 1 5); do
+	    # Expire route after $EXPIRE seconds
+	    $IP -6 route replace 2001:20::$i \
+		via 2001:10::2 dev dummy_10 expires $EXPIRE
+	done
+	N_EXP=$($IP -6 route list |grep expires|wc -l)
+	if [ $N_EXP -ne 5 ]; then
+	    log_test 1 0 "expected 5 routes with expires, got $N_EXP"
+	    set +e
+	    cleanup &> /dev/null
+	    return
+	fi
+	# Wait for GC
+	sleep $(($EXPIRE * 2 + 1))
+	N_EXP=$($IP -6 route list |grep expires|wc -l)
+	if [ $N_EXP -ne 0 ]; then
+	    echo "FAIL: expected 0 routes with expires, got $N_EXP"
+	    ret=1
+	else
+	    ret=0
+	fi
+
+	log_test $ret 0 "ipv6 route garbage collection (replace with expires)"
+
+	reset_dummy_10
+
+	# Temporary routes
+	for i in $(seq 1 5); do
+	    # Expire route after $EXPIRE seconds
+	    $IP -6 route add 2001:20::$i \
+		via 2001:10::2 dev dummy_10 expires $EXPIRE
+	done
+	# Replace with permanent routes
+	for i in $(seq 1 5); do
+	    $IP -6 route replace 2001:20::$i \
+		via 2001:10::2 dev dummy_10
+	done
+	N_EXP=$($IP -6 route list |grep expires|wc -l)
+	if [ $N_EXP -ne 0 ]; then
+	    log_test 1 0 "expected 0 routes with expires, got $N_EXP"
+	    set +e
+	    cleanup &> /dev/null
+	    return
+	fi
+
+	# Wait for GC
+	sleep $(($EXPIRE * 2 + 1))
+
+	N_PERM=$($IP -6 route list |grep -v expires|grep 2001:20::|wc -l)
+	if [ $N_PERM -ne 5 ]; then
+	    echo "FAIL: expected 5 permanent routes, got $N_PERM"
+	    ret=1
+	else
+	    ret=0
+	fi
+
+	log_test $ret 0 "ipv6 route garbage collection (replace with permanent)"
+
+	# ra6 is required for the next test. (ipv6toolkit)
+	if [ ! -x "$(command -v ra6)" ]; then
+	    echo "SKIP: ra6 not found."
+	    set +e
+	    cleanup &> /dev/null
+	    return
+	fi
+
+	# Delete dummy_10 and remove all routes
+	$IP link del dev dummy_10
+
+	# Create a pair of veth devices to send a RA message from one
+	# device to another.
+	$IP link add veth1 type veth peer name veth2
+	$IP link set dev veth1 up
+	$IP link set dev veth2 up
+	$IP -6 address add 2001:10::1/64 dev veth1 nodad
+	$IP -6 address add 2001:10::2/64 dev veth2 nodad
+
+	# Make veth1 ready to receive RA messages.
+	$NS_EXEC sysctl -wq net.ipv6.conf.veth1.accept_ra=2
+
+	# Send a RA message with a route from veth2 to veth1.
+	$NS_EXEC ra6 -i veth2 -d 2001:10::1 -t $EXPIRE
+
+	# Wait for the RA message.
+	sleep 1
+
+	N_EXP=$($IP -6 route list|grep expires|wc -l)
+	if [ $N_EXP -ne 1 ]; then
+	    # systemd may mess up the test.  Make sure that
+	    # systemd-networkd.service and systemd-networkd.socket are
+	    # stopped.
+	    log_test 1 0 "expected 1 routes with expires, got $N_EXP"
+	    set +e
+	    cleanup &> /dev/null
+	    return
+	fi
+
+	# Wait for GC
+	sleep $(($EXPIRE * 2 + 1))
+
+	N_EXP=$($IP -6 route list |grep expires|wc -l)
+	if [ $N_EXP -ne 0 ]; then
+	    echo "FAIL: expected 0 routes with expires, got $N_EXP"
+	    ret=1
+	else
+	    ret=0
+	fi
+
+	log_test $ret 0 "ipv6 route garbage collection (RA message)"
+
+	set +e
 
 	cleanup &> /dev/null
 }