sp.diff

diff --git a/lib/Mojo/IOLoop/Subprocess.pm b/lib/Mojo/IOLoop/Subprocess.pm
index 0093df73b..f61fde9c0 100644
--- a/lib/Mojo/IOLoop/Subprocess.pm
+++ b/lib/Mojo/IOLoop/Subprocess.pm
@@ -12,6 +12,8 @@ has deserialize => sub { \&Storable::thaw };
 has ioloop      => sub { Mojo::IOLoop->singleton };
 has serialize   => sub { \&Storable::freeze };

+sub DESTROY { kill 'KILL', $_[0]{pid} if $_[0]{pid} }
+
 sub pid { shift->{pid} }

 sub run {
@@ -45,6 +47,7 @@ sub run {
       waitpid $pid, 0;
       my $results = eval { $self->deserialize->($buffer) } || [];
       $self->$parent(shift(@$results) // $@, @$results);
+      delete $self->{pid};
     }
   );
   return $self;