lib/PublicInbox/Spawn.pm | 2 +-

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index 2d9f734c1b6df46331a86f2802b1aa3972fee004..ad6be1878a0fd899c8a7543645cbae2285bf6fa2 100644
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -210,7 +210,7 @@ 		push @$rlim, $r, @$v;
 	}
 	my $cd = $opts->{'-C'} // ''; # undef => NULL mapping doesn't work?
 	my $pid = pi_fork_exec($redir, $f, $cmd, \@env, $rlim, $cd);
-	die "fork_exec failed: $!\n" unless defined $pid;
+	die "fork_exec failed: $!\n" unless $pid > 0;
 	$pid;
 }