diff --git a/src/basic/terminal-util.c b/src/basic/terminal-util.c
index 4702e91732..ab8917ccc5 100644
--- a/src/basic/terminal-util.c
+++ b/src/basic/terminal-util.c
@@ -891,33 +891,24 @@ bool on_tty(void) {
 }
 
 int getttyname_malloc(int fd, char **ret) {
-        size_t l = 100;
+        char path[PATH_MAX], *c; /* PATH_MAX is counted *with* the trailing NUL byte */
         int r;
 
         assert(fd >= 0);
         assert(ret);
 
-        for (;;) {
-                char path[l];
+        r = ttyname_r(fd, path, sizeof path); /* positive error */
+        assert(r >= 0);
+        if (r == ERANGE)
+                return -ENAMETOOLONG;
+        if (r > 0)
+                return -r;
 
-                r = ttyname_r(fd, path, sizeof(path));
-                if (r == 0) {
-                        char *c;
-
-                        c = strdup(skip_dev_prefix(path));
-                        if (!c)
-                                return -ENOMEM;
-
-                        *ret = c;
-                        return 0;
-                }
-
-                if (r != ERANGE)
-                        return -r;
-
-                l *= 2;
-        }
+        c = strdup(skip_dev_prefix(path));
+        if (!c)
+                return -ENOMEM;
 
+        *ret = c;
         return 0;
 }
 
diff --git a/src/test/test-terminal-util.c b/src/test/test-terminal-util.c
index 958d369430..e510b737c7 100644
--- a/src/test/test-terminal-util.c
+++ b/src/test/test-terminal-util.c
@@ -6,6 +6,7 @@
 #include "alloc-util.h"
 #include "fd-util.h"
 #include "macro.h"
+#include "path-util.h"
 #include "strv.h"
 #include "terminal-util.h"
 #include "tests.h"
@@ -52,7 +53,16 @@ static void test_read_one_char(void) {
         rewind(file);
         assert_se(read_one_char(file, &r, 1000000, &need_nl) < 0);
 
-        unlink(name);
+        assert_se(unlink(name) >= 0);
+}
+
+static void test_getttyname_malloc(void) {
+        _cleanup_free_ char *ttyname = NULL;
+        _cleanup_close_ int master = -1;
+
+        assert_se((master = posix_openpt(O_RDWR|O_NOCTTY)) >= 0);
+        assert_se(getttyname_malloc(master, &ttyname) >= 0);
+        assert_se(PATH_IN_SET(ttyname, "ptmx", "pts/ptmx"));
 }
 
 int main(int argc, char *argv[]) {
@@ -60,6 +70,7 @@ int main(int argc, char *argv[]) {
 
         test_default_term_for_tty();
         test_read_one_char();
+        test_getttyname_malloc();
 
         return 0;
 }