diff --git a/src/basic/strxcpyx.c b/src/basic/strxcpyx.c
index 9126e1dfe2..dc40d620e7 100644
--- a/src/basic/strxcpyx.c
+++ b/src/basic/strxcpyx.c
@@ -41,7 +41,7 @@ size_t strnpcpy_full(char **dest, size_t size, const char *src, size_t len, bool
         if (ret_truncated)
                 *ret_truncated = truncated;
 
-        *dest[0] = '\0';
+        (*dest)[0] = '\0';
         return size;
 }
 
diff --git a/src/core/exec-invoke.c b/src/core/exec-invoke.c
index aaa9a0e8bd..2448baa125 100644
--- a/src/core/exec-invoke.c
+++ b/src/core/exec-invoke.c
@@ -77,6 +77,7 @@
 #include "stat-util.h"
 #include "string-table.h"
 #include "strv.h"
+#include "strxcpyx.h"
 #include "terminal-util.h"
 #include "user-util.h"
 #include "utmp-wtmp.h"
@@ -1504,7 +1505,7 @@ static void rename_process_from_path(const char *path) {
         size_t len = strlen(buf);
         char comm[TASK_COMM_LEN], *p = comm;
         *p++ = '(';
-        p = mempcpy(p, buf + LESS_BY(len, (size_t) (TASK_COMM_LEN - 3)), MIN(len, (size_t) (TASK_COMM_LEN - 3)));
+        strnpcpy(&p, TASK_COMM_LEN - 2, buf, len); /* strnpcpy() accounts for NUL byte internally */
         *p++ = ')';
         *p = '\0';