diff --git a/bugfix-dhcp-4.2.5-check-dhclient-pid.patch b/bugfix-dhcp-4.2.5-check-dhclient-pid.patch
deleted file mode 100644
index d771445..0000000
--- a/bugfix-dhcp-4.2.5-check-dhclient-pid.patch
+++ /dev/null
@@ -1,75 +0,0 @@
---- a/client/dhclient.c	2019-01-25 14:34:46.996000000 +0800
-+++ b/client/dhclient.c	2019-01-25 14:34:16.382000000 +0800
-@@ -114,6 +114,8 @@
- 
- int bootp_broadcast_always = 0;
- 
-+int buf_size = 128;
-+
- extern struct option *default_requested_options[];
- 
- void run_stateless(int exit_mode, u_int16_t port);
-@@ -129,6 +131,8 @@
- static void dhclient_ddns_cb_free(dhcp_ddns_cb_t *ddns_cb,
-                                    char* file, int line);
- 
-+static int check_dhclient_pid(pid_t pid);
-+
- /*!
-  *
-  * \brief Print the generic usage message
-@@ -682,7 +686,8 @@
- 			e = fscanf(pidfd, "%ld\n", &temp);
- 			oldpid = (pid_t)temp;
- 
--			if (e != 0 && e != EOF && oldpid) {
-+			if (e != 0 && e != EOF) {
-+			 if (oldpid && check_dhclient_pid(oldpid)) {
- 				if (kill(oldpid, SIGTERM) == 0) {
- 					log_info("Killed old client process");
- 					(void) unlink(path_dhclient_pid);
-@@ -698,6 +703,7 @@
- 					log_info("Removed stale PID file");
- 					(void) unlink(path_dhclient_pid);
- 				}
-+				 }
- 			}
- 			fclose(pidfd);
- 		} else {
-@@ -738,7 +744,7 @@
- 						oldpid = (pid_t)temp;
- 
- 						if (e != 0 && e != EOF) {
--							if (oldpid) {
-+							if (oldpid && check_dhclient_pid(oldpid)) {
- 								if (kill(oldpid, SIGTERM) == 0)
- 									unlink(path_dhclient_pid);
- 							}
-@@ -6045,3 +6051,27 @@
- 		log_error("dhcp4o6_stop: send(): %m");
- }
- #endif /* DHCPv6 && DHCP4o6 */
-+
-+static int check_dhclient_pid(pid_t pid) {
-+	char proc_pid_path[buf_size];
-+	char task_name[buf_size];
-+
-+	memset(proc_pid_path, 0, buf_size);
-+	memset(task_name, 0, buf_size);
-+
-+	snprintf(proc_pid_path, buf_size - 1, "/proc/%d/comm", pid);
-+
-+	FILE* fp = fopen(proc_pid_path, "r");
-+	if(fp != NULL) {
-+		if( fgets(task_name, buf_size, fp) == NULL ) {
-+			fclose(fp);
-+			return 0;
-+		 }
-+		fclose(fp);
-+		if(strncmp(task_name, "dhclient", 8) == 0) {
-+			return 1;
-+		}
-+	}
-+
-+	 return 0;
-+}