diff --git a/src/oom/oomd.c b/src/oom/oomd.c
index 518ddc47c1..53c4948a73 100644
--- a/src/oom/oomd.c
+++ b/src/oom/oomd.c
@@ -115,10 +115,12 @@ static int run(int argc, char *argv[]) {
          * requirements do not have a reliable means to check for in code. */
 
         int n = sd_listen_fds(0);
+        if (n < 0)
+                return log_error_errno(n, "Failed to determine number of listening fds: %m");
         if (n > 1)
                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Received too many file descriptors");
 
-        int fd = n == 1 ? SD_LISTEN_FDS_START : -1;
+        int fd = n == 1 ? SD_LISTEN_FDS_START : -EBADF;
 
         /* SwapTotal is always available in /proc/meminfo and defaults to 0, even on swap-disabled kernels. */
         r = get_proc_field("/proc/meminfo", "SwapTotal", WHITESPACE, &swap);