diff --git a/src/haproxy.c b/src/haproxy.c
index fe612b0c1..804e092d2 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -2147,7 +2147,7 @@ static void init(int argc, char **argv)
 			}
 			tmproc->options |= PROC_O_TYPE_MASTER; /* master */
 			tmproc->pid = pid;
-			tmproc->timestamp = start_time.tv_sec;
+			tmproc->timestamp = start_date.tv_sec;
 			proc_self = tmproc;
 
 			LIST_APPEND(&proc_list, &tmproc->list);
@@ -3563,7 +3563,7 @@ int main(int argc, char **argv)
 						if (child->reloads == 0 &&
 						    child->options & PROC_O_TYPE_WORKER &&
 						    child->pid == -1) {
-							child->timestamp = now.tv_sec;
+							child->timestamp = date.tv_sec;
 							child->pid = ret;
 							child->version = strdup(haproxy_version);
 							break;
diff --git a/src/mworker.c b/src/mworker.c
index 8b3be1916..4bc224ee7 100644
--- a/src/mworker.c
+++ b/src/mworker.c
@@ -530,13 +530,16 @@ static int cli_io_handler_show_proc(struct appctx *appctx)
 	struct stconn *sc = appctx_sc(appctx);
 	struct mworker_proc *child;
 	int old = 0;
-	int up = now.tv_sec - proc_self->timestamp;
+	int up = date.tv_sec - proc_self->timestamp;
 	char *uptime = NULL;
 	char *reloadtxt = NULL;
 
 	if (unlikely(sc_ic(sc)->flags & CF_SHUTW))
 		return 1;
 
+	if (up < 0) /* must never be negative because of clock drift */
+		up = 0;
+
 	chunk_reset(&trash);
 
 	memprintf(&reloadtxt, "%d [failed: %d]", proc_self->reloads, proc_self->failedreloads);
@@ -550,7 +553,9 @@ static int cli_io_handler_show_proc(struct appctx *appctx)
 
 	chunk_appendf(&trash, "# workers\n");
 	list_for_each_entry(child, &proc_list, list) {
-		up = now.tv_sec - child->timestamp;
+		up = date.tv_sec - child->timestamp;
+		if (up < 0) /* must never be negative because of clock drift */
+			up = 0;
 
 		if (!(child->options & PROC_O_TYPE_WORKER))
 			continue;
@@ -571,7 +576,9 @@ static int cli_io_handler_show_proc(struct appctx *appctx)
 
 		chunk_appendf(&trash, "# old workers\n");
 		list_for_each_entry(child, &proc_list, list) {
-			up = now.tv_sec - child->timestamp;
+			up = date.tv_sec - child->timestamp;
+			if (up <= 0) /* must never be negative because of clock drift */
+				up = 0;
 
 			if (!(child->options & PROC_O_TYPE_WORKER))
 				continue;
@@ -589,7 +596,9 @@ static int cli_io_handler_show_proc(struct appctx *appctx)
 	chunk_appendf(&trash, "# programs\n");
 	old = 0;
 	list_for_each_entry(child, &proc_list, list) {
-		up = now.tv_sec - child->timestamp;
+		up = date.tv_sec - child->timestamp;
+		if (up < 0) /* must never be negative because of clock drift */
+			up = 0;
 
 		if (!(child->options & PROC_O_TYPE_PROG))
 			continue;
@@ -606,7 +615,9 @@ static int cli_io_handler_show_proc(struct appctx *appctx)
 	if (old) {
 		chunk_appendf(&trash, "# old programs\n");
 		list_for_each_entry(child, &proc_list, list) {
-			up = now.tv_sec - child->timestamp;
+			up = date.tv_sec - child->timestamp;
+			if (up < 0) /* must never be negative because of clock drift */
+				up = 0;
 
 			if (!(child->options & PROC_O_TYPE_PROG))
 				continue;