diff --git a/src/logging.c b/src/logging.c
index 0816570..f58265f 100644
--- a/src/logging.c
+++ b/src/logging.c
@@ -175,17 +175,19 @@
 	category_token = strtok(mask, ":");
 	do {
 		for (i = 0; i < osmo_log_info->num_cat; ++i) {
+			size_t length, cat_length;
 			char* colon = strstr(category_token, ",");
-			int length = strlen(category_token);
-			int cat_length = strlen(osmo_log_info->cat[i].name);
+
+			if (!osmo_log_info->cat[i].name)
+				continue;
+
+			length = strlen(category_token);
+			cat_length = strlen(osmo_log_info->cat[i].name);
 
 			/* Use longest length not to match subocurrences. */
 			if (cat_length > length)
 				length = cat_length;
 
-			if (!osmo_log_info->cat[i].name)
-				continue;
-
 			if (colon)
 			    length = colon - category_token;