diff --git a/sapi/fpm/fpm/fpm_conf.c b/sapi/fpm/fpm/fpm_conf.c
index 3979d875a18e..a13c91e8facc 100644
--- a/sapi/fpm/fpm/fpm_conf.c
+++ b/sapi/fpm/fpm/fpm_conf.c
@@ -972,7 +972,8 @@ static int fpm_conf_process_all_pools(void)
 				return -1;
 			}
 
-			for (i = 0; i < strlen(status); i++) {
+			size_t status_len = strlen(status);
+			for (i = 0; i < status_len; i++) {
 				if (!isalnum(status[i]) && status[i] != '/' && status[i] != '-' && status[i] != '_' && status[i] != '.' && status[i] != '~') {
 					zlog(ZLOG_ERROR, "[pool %s] the status path '%s' must contain only the following characters '[alphanum]/_-.~'", wp->config->name, status);
 					return -1;
@@ -995,7 +996,8 @@ static int fpm_conf_process_all_pools(void)
 				return -1;
 			}
 
-			for (i = 0; i < strlen(ping); i++) {
+			size_t ping_len = strlen(ping);
+			for (i = 0; i < ping_len; i++) {
 				if (!isalnum(ping[i]) && ping[i] != '/' && ping[i] != '-' && ping[i] != '_' && ping[i] != '.' && ping[i] != '~') {
 					zlog(ZLOG_ERROR, "[pool %s] the ping path '%s' must contain only the following characters '[alphanum]/_-.~'", wp->config->name, ping);
 					return -1;