BUG#45511 rpl.rpl_binlog_corruption fails with warning messages in Valgrind

This is a backport of BUG#43076.

sql/rpl_reporting.cc

@@ -13,6 +13,7 @@ Slave_reporting_capability::report(loglevel level, int err_code,
   va_list args;
   va_start(args, msg);
 
+  pthread_mutex_lock(&err_lock);
   switch (level)
   {
   case ERROR_LEVEL:
@@ -38,6 +39,7 @@ Slave_reporting_capability::report(loglevel level, int err_code,
 
   my_vsnprintf(pbuff, pbuffsize, msg, args);
 
+  pthread_mutex_unlock(&err_lock);
   va_end(args);
 
   /* If the msg string ends with '.', do not add a ',' it would be ugly */
@@ -46,3 +48,8 @@ Slave_reporting_capability::report(loglevel level, int err_code,
                   (pbuff[0] && *(strend(pbuff)-1) == '.') ? "" : ",",
                   err_code);
 }
+
+Slave_reporting_capability::~Slave_reporting_capability()
+{
+  pthread_mutex_destroy(&err_lock);
+}

sql/rpl_reporting.h

@@ -16,6 +16,8 @@
 class Slave_reporting_capability
 {
 public:
+  /** lock used to synchronize m_last_error on 'SHOW SLAVE STATUS' **/
+  mutable pthread_mutex_t err_lock;
   /**
      Constructor.
 
@@ -24,6 +26,7 @@ class Slave_reporting_capability
   Slave_reporting_capability(char const *thread_name)
     : m_thread_name(thread_name)
   {
+      pthread_mutex_init(&err_lock, MY_MUTEX_INIT_FAST);
   }
 
   /**
@@ -44,7 +47,9 @@ class Slave_reporting_capability
      STATUS</code>.
    */
   void clear_error() {
+    pthread_mutex_lock(&err_lock);
     m_last_error.clear();
+    pthread_mutex_unlock(&err_lock);
   }
 
   /**
@@ -72,6 +77,7 @@ class Slave_reporting_capability
 
   Error const& last_error() const { return m_last_error; }
 
+  virtual ~Slave_reporting_capability()= 0;
 private:
   /**
      Last error produced by the I/O or SQL thread respectively.
@@ -79,6 +85,10 @@ class Slave_reporting_capability
   mutable Error m_last_error;
 
   char const *const m_thread_name;
+
+  // not implemented
+  Slave_reporting_capability(const Slave_reporting_capability& rhs);
+  Slave_reporting_capability& operator=(const Slave_reporting_capability& rhs);
 };
 
 #endif // RPL_REPORTING_H

sql/slave.cc

@@ -1493,6 +1493,8 @@ bool show_master_info(THD* thd, Master_info* mi)
 
     pthread_mutex_lock(&mi->data_lock);
     pthread_mutex_lock(&mi->rli.data_lock);
+    pthread_mutex_lock(&mi->err_lock);
+    pthread_mutex_lock(&mi->rli.err_lock);
     protocol->store(mi->host, &my_charset_bin);
     protocol->store(mi->user, &my_charset_bin);
     protocol->store((uint32) mi->port);
@@ -1592,6 +1594,8 @@ bool show_master_info(THD* thd, Master_info* mi)
     // Last_SQL_Error
     protocol->store(mi->rli.last_error().message, &my_charset_bin);
 
+    pthread_mutex_unlock(&mi->rli.err_lock);
+    pthread_mutex_unlock(&mi->err_lock);
     pthread_mutex_unlock(&mi->rli.data_lock);
     pthread_mutex_unlock(&mi->data_lock);