diff --git a/src/NetworkManagerUtils.c b/src/NetworkManagerUtils.c
index b59203255f..088811b5f2 100644
--- a/src/NetworkManagerUtils.c
+++ b/src/NetworkManagerUtils.c
@@ -482,7 +482,7 @@ guint64
 nm_utils_get_start_time_for_pid (pid_t pid, char *out_state, pid_t *out_ppid)
 {
 	guint64 start_time;
-	gs_free gchar *filename = NULL;
+	char filename[256];
 	gs_free gchar *contents = NULL;
 	size_t length;
 	gs_strfreev gchar **tokens = NULL;
@@ -497,7 +497,7 @@ nm_utils_get_start_time_for_pid (pid_t pid, char *out_state, pid_t *out_ppid)
 
 	g_return_val_if_fail (pid > 0, 0);
 
-	filename = g_strdup_printf ("/proc/%"G_GUINT64_FORMAT"/stat", (guint64) pid);
+	nm_sprintf_buf (filename, "/proc/%"G_GUINT64_FORMAT"/stat", (guint64) pid);
 
 	if (!g_file_get_contents (filename, &contents, &length, NULL))
 		goto out;
diff --git a/src/dnsmasq-manager/nm-dnsmasq-manager.c b/src/dnsmasq-manager/nm-dnsmasq-manager.c
index f4a6208d05..41184910db 100644
--- a/src/dnsmasq-manager/nm-dnsmasq-manager.c
+++ b/src/dnsmasq-manager/nm-dnsmasq-manager.c
@@ -33,6 +33,7 @@
 #include "nm-dnsmasq-utils.h"
 #include "nm-utils.h"
 #include "NetworkManagerUtils.h"
+#include "nm-core-internal.h"
 
 typedef struct {
 	char *iface;
@@ -211,19 +212,20 @@ dm_watch_cb (GPid pid, gint status, gpointer user_data)
 
 static NMCmdLine *
 create_dm_cmd_line (const char *iface,
-                    NMIP4Config *ip4_config,
+                    const NMPlatformIP4Address *listen_address,
                     const char *pidfile,
                     GError **error)
 {
 	NMCmdLine *cmd;
 	GString *s;
-	const NMPlatformIP4Address *tmp;
 	char first[INET_ADDRSTRLEN];
 	char last[INET_ADDRSTRLEN];
 	char localaddr[INET_ADDRSTRLEN];
 	char *error_desc = NULL;
 	const char *dm_binary;
 
+	g_return_val_if_fail (listen_address, NULL);
+
 	dm_binary = nm_utils_find_helper ("dnsmasq", DNSMASQ_PATH, error);
 	if (!dm_binary)
 		return NULL;
@@ -257,16 +259,13 @@ create_dm_cmd_line (const char *iface,
 	 */
 	nm_cmd_line_add_string (cmd, "--strict-order");
 
-	/* Find the IP4 address to use */
-	tmp = nm_ip4_config_get_address (ip4_config, 0);
-
 	s = g_string_new ("--listen-address=");
-	nm_utils_inet4_ntop (tmp->address, localaddr);
+	nm_utils_inet4_ntop (listen_address->address, localaddr);
 	g_string_append (s, localaddr);
 	nm_cmd_line_add_string (cmd, s->str);
 	g_string_free (s, TRUE);
 
-	if (!nm_dnsmasq_utils_get_range (tmp, first, last, &error_desc)) {
+	if (!nm_dnsmasq_utils_get_range (listen_address, first, last, &error_desc)) {
 		g_set_error_literal (error,
 		                     NM_MANAGER_ERROR,
 		                     NM_MANAGER_ERROR_FAILED,
@@ -302,35 +301,41 @@ create_dm_cmd_line (const char *iface,
 }
 
 static void
-kill_existing_for_iface (const char *iface, const char *pidfile)
+kill_existing_by_pidfile (const char *pidfile)
 {
 	char *contents = NULL;
-	glong pid;
-	char *proc_path = NULL;
+	pid_t pid;
+	char proc_path[250];
 	char *cmdline_contents = NULL;
+	guint64 start_time;
+	const char *exe;
 
-	if (!g_file_get_contents (pidfile, &contents, NULL, NULL))
+	if (   !pidfile
+	    || !g_file_get_contents (pidfile, &contents, NULL, NULL))
+		return;
+
+	pid = _nm_utils_ascii_str_to_int64 (contents, 10, 1, G_MAXUINT64, 0);
+	if (pid == 0)
 		goto out;
 
-	pid = strtol (contents, NULL, 10);
-	if (pid < 1 || pid > INT_MAX)
+	start_time = nm_utils_get_start_time_for_pid (pid, NULL, NULL);
+	if (start_time == 0)
 		goto out;
 
-	proc_path = g_strdup_printf ("/proc/%ld/cmdline", pid);
+	nm_sprintf_buf (proc_path, "/proc/%lld/cmdline", (long long) pid);
 	if (!g_file_get_contents (proc_path, &cmdline_contents, NULL, NULL))
 		goto out;
 
-	if (strstr (cmdline_contents, "bin/dnsmasq")) {
-		if (kill (pid, 0) == 0) {
-			nm_log_dbg (LOGD_SHARING, "Killing stale dnsmasq process %ld", pid);
-			kill (pid, SIGKILL);
-		}
-		unlink (pidfile);
+	exe = strrchr (cmdline_contents, '/');
+	if (   (exe && strcmp (&exe[1], "dnsmasq") == 0)
+	    || (strcmp (cmdline_contents, DNSMASQ_PATH) == 0)) {
+		nm_utils_kill_process_sync (pid, start_time, SIGKILL, LOGD_SHARING,
+		                            "dnsmasq", 0, 0, 500);
 	}
 
 out:
+	unlink (pidfile);
 	g_free (cmdline_contents);
-	g_free (proc_path);
 	g_free (contents);
 }
 
@@ -344,14 +349,14 @@ nm_dnsmasq_manager_start (NMDnsMasqManager *manager,
 	gs_free char *cmd_str = NULL;
 
 	g_return_val_if_fail (NM_IS_DNSMASQ_MANAGER (manager), FALSE);
-	if (error)
-		g_return_val_if_fail (*error == NULL, FALSE);
+	g_return_val_if_fail (!error || !*error, FALSE);
+	g_return_val_if_fail (nm_ip4_config_get_num_addresses (ip4_config) > 0, FALSE);
 
 	priv = NM_DNSMASQ_MANAGER_GET_PRIVATE (manager);
 
-	kill_existing_for_iface (priv->iface, priv->pidfile);
+	kill_existing_by_pidfile (priv->pidfile);
 
-	dm_cmd = create_dm_cmd_line (priv->iface, ip4_config, priv->pidfile, error);
+	dm_cmd = create_dm_cmd_line (priv->iface, nm_ip4_config_get_address (ip4_config, 0), priv->pidfile, error);
 	if (!dm_cmd)
 		return FALSE;