lib/PublicInbox/Spawn.pm | 2 ++

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index 394a0b453e342cdf3ef4a2ac328d1125aa6721e6..72cd6c3cc4fce032bb8ce36b025854dbeb5b67b4 100644
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -111,7 +111,9 @@ 		my $f = "$inline_dir/.public-inbox.lock";
 		open my $fh, '>', $f or die "failed to open $f: $!\n";
 		flock($fh, LOCK_EX) or die "LOCK_EX failed on $f: $!\n";
 		eval 'use Inline C => $vfork_spawn';
+		my $err = $@;
 		flock($fh, LOCK_UN) or die "LOCK_UN failed on $f: $!\n";
+		die $err if $err;
 	};
 	if ($@) {
 		warn "Inline::C failed for vfork: $@\n";