Bug#43706: libmysqld segfaults when re-intialised

Bug#44091: libmysqld gets stuck waiting on mutex on initialization

The problem was that libmysqld wasn't enforcing a certain
initialization and deinitialization order for the mysys
library. Another problem was that the global object used
for management of log event handlers (aka LOGGER) wasn't
being prepared for a possible reutilization.

What leads to the hang/crash reported is that a failure
to load the language file triggers a double call of the
cleanup functions, causing an already destroyed mutex to
be used.

The solution is enforce a order on the initialization and
deinitialization of the mysys library within the libmysqld
library and to ensure that the global LOGGER object reset
it's internal state during cleanup.

mysys/my_init.c:
  Deinitialize only if initialized already.
sql/log.cc:
  Reset state.

1 files changed, 5 insertions, 0 deletions

diff --git a/sql/log.cc b/sql/log.cc
index 44296daa939..ed2eff6625d 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -845,6 +845,7 @@ void LOGGER::cleanup_base()
   {
     table_log_handler->cleanup();
     delete table_log_handler;
+    table_log_handler= NULL;
   }
   if (file_log_handler)
     file_log_handler->cleanup();
@@ -855,7 +856,11 @@ void LOGGER::cleanup_end()
 {
   DBUG_ASSERT(inited == 1);
   if (file_log_handler)
+  {
     delete file_log_handler;
+    file_log_handler=NULL;
+  }
+  inited= 0;
 }