thread_group_close does not unlock mutex in error branches

[Laurynas Biveinis]

Spotted over at MariaDB:

https://github.com/MariaDB/server/pull/413

diff --git a/sql/threadpool_unix.cc b/sql/threadpool_unix.cc
index 6075c758e405..0ffe08a80518 100644
--- a/sql/threadpool_unix.cc
+++ b/sql/threadpool_unix.cc
@@ -979,24 +979,26 @@ static void thread_group_close(thread_group_t *thread_group)

   if (pipe(thread_group->shutdown_pipe))
   {
- DBUG_VOID_RETURN;
+ goto end;
   }

   /* Wake listener */
   if (io_poll_associate_fd(thread_group->pollfd,
       thread_group->shutdown_pipe[0], NULL))
   {
- DBUG_VOID_RETURN;
+ goto end;
+ }
+ {
+ char c= 0;
+ if (write(thread_group->shutdown_pipe[1], &c, 1) < 0)
+ goto end;
   }
- char c= 0;
- if (write(thread_group->shutdown_pipe[1], &c, 1) < 0)
- DBUG_VOID_RETURN;
-
   /* Wake all workers. */
   while(wake_thread(thread_group) == 0)
   {
   }

+end:
   mysql_mutex_unlock(&thread_group->mutex);

   DBUG_VOID_RETURN;

[Zsolt Parragi (zsolt.parragi)]

https://github.com/percona/percona-server/pull/1989
https://github.com/percona/percona-server/pull/1990
https://github.com/percona/percona-server/pull/1991

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-1103