diff --git a/src/core/dhcp/nm-dhcp-client.c b/src/core/dhcp/nm-dhcp-client.c
index 0dc21be630..da99cbb644 100644
--- a/src/core/dhcp/nm-dhcp-client.c
+++ b/src/core/dhcp/nm-dhcp-client.c
@@ -83,6 +83,11 @@ G_DEFINE_ABSTRACT_TYPE(NMDhcpClient, nm_dhcp_client, G_TYPE_OBJECT)
 
 /*****************************************************************************/
 
+/* we use pid=-1 for invalid PIDs. Ensure that pid_t can hold negative values. */
+G_STATIC_ASSERT(!(((pid_t) -1) > 0));
+
+/*****************************************************************************/
+
 pid_t
 nm_dhcp_client_get_pid(NMDhcpClient *self)
 {
diff --git a/src/core/dhcp/nm-dhcp-dhcpcd.c b/src/core/dhcp/nm-dhcp-dhcpcd.c
index 8c31aed0cf..64187b8eb3 100644
--- a/src/core/dhcp/nm-dhcp-dhcpcd.c
+++ b/src/core/dhcp/nm-dhcp-dhcpcd.c
@@ -169,27 +169,29 @@ stop(NMDhcpClient *client, gboolean release)
     int           sig, errsv;
 
     pid = nm_dhcp_client_get_pid(client);
-    sig = release ? SIGALRM : SIGTERM;
-    _LOGD("sending %s to dhcpcd pid %d", sig == SIGALRM ? "SIGALRM" : "SIGTERM", pid);
+    if (pid > 1) {
+        sig = release ? SIGALRM : SIGTERM;
+        _LOGD("sending %s to dhcpcd pid %d", sig == SIGALRM ? "SIGALRM" : "SIGTERM", pid);
 
-    /* dhcpcd-9.x features privilege separation.
-     * It's not our job to track all these processes so we rely on dhcpcd
-     * to always cleanup after itself.
-     * Because it also re-parents itself to PID 1, the process cannot be
-     * reaped or waited for.
-     * As such, just send the correct signal.
-     */
-    if (kill(pid, sig) == -1) {
-        errsv = errno;
-        _LOGE("failed to kill dhcpcd %d:%s", errsv, strerror(errsv));
+        /* dhcpcd-9.x features privilege separation.
+         * It's not our job to track all these processes so we rely on dhcpcd
+         * to always cleanup after itself.
+         * Because it also re-parents itself to PID 1, the process cannot be
+         * reaped or waited for.
+         * As such, just send the correct signal.
+         */
+        if (kill(pid, sig) == -1) {
+            errsv = errno;
+            _LOGE("failed to kill dhcpcd %d:%s", errsv, strerror(errsv));
+        }
+
+        /* When this function exits NM expects the PID to be -1.
+         * This means we also need to stop watching the pid.
+         * If we need to know the exit status then we need to refactor NM
+         * to allow a non -1 to mean we're waiting to exit still.
+         */
+        nm_dhcp_client_stop_watch_child(client, pid);
     }
-
-    /* When this function exits NM expects the PID to be -1.
-     * This means we also need to stop watching the pid.
-     * If we need to know the exit status then we need to refactor NM
-     * to allow a non -1 to mean we're waiting to exit still.
-     */
-    nm_dhcp_client_stop_watch_child(client, pid);
 }
 
 /*****************************************************************************/