Bug #38883 (reopened): thd_security_context is not thread safe, crashes?

manual merge 5.0-->5.1, updating InnoDB plugin.

sql/sql_class.cc

@@ -376,6 +376,8 @@ char *thd_security_context(THD *thd, char *buffer, unsigned int length,
     str.append(proc_info);
   }
 
+  pthread_mutex_lock(&thd->LOCK_thd_data);
+
   if (thd->query())
   {
     if (max_query_len < 1)
@@ -385,6 +387,9 @@ char *thd_security_context(THD *thd, char *buffer, unsigned int length,
     str.append('\n');
     str.append(thd->query(), len);
   }
+
+  pthread_mutex_unlock(&thd->LOCK_thd_data);
+
   if (str.c_ptr_safe() == buffer)
     return buffer;
 

storage/innobase/handler/ha_innodb.cc

@@ -770,35 +770,6 @@ convert_error_code_to_mysql(
     	}
 }
 
-/*****************************************************************
-If you want to print a thd that is not associated with the current thread,
-you must call this function before reserving the InnoDB kernel_mutex, to
-protect MySQL from setting thd->query NULL. If you print a thd of the current
-thread, we know that MySQL cannot modify thd->query, and it is not necessary
-to call this. Call innobase_mysql_end_print_arbitrary_thd() after you release
-the kernel_mutex.
-NOTE that /mysql/innobase/lock/lock0lock.c must contain the prototype for this
-function! */
-extern "C"
-void
-innobase_mysql_prepare_print_arbitrary_thd(void)
-/*============================================*/
-{
-	VOID(pthread_mutex_lock(&LOCK_thread_count));
-}
-
-/*****************************************************************
-Releases the mutex reserved by innobase_mysql_prepare_print_arbitrary_thd().
-NOTE that /mysql/innobase/lock/lock0lock.c must contain the prototype for this
-function! */
-extern "C"
-void
-innobase_mysql_end_print_arbitrary_thd(void)
-/*========================================*/
-{
-	VOID(pthread_mutex_unlock(&LOCK_thread_count));
-}
-
 /*****************************************************************
 Prints info of a THD object (== user session thread) to the given file.
 NOTE that /mysql/innobase/trx/trx0trx.c must contain the prototype for

storage/innobase/include/trx0trx.h

@@ -318,9 +318,7 @@ trx_commit_step(
 
 /**************************************************************************
 Prints info about a transaction to the given file. The caller must own the
-kernel mutex and must have called
-innobase_mysql_prepare_print_arbitrary_thd(), unless he knows that MySQL
-or InnoDB cannot meanwhile change the info printed here. */
+kernel mutex. */
 
 void
 trx_print(

storage/innobase/lock/lock0lock.c

@@ -22,31 +22,6 @@ Created 5/7/1996 Heikki Tuuri
 #include "trx0sys.h"
 
 
-/* 2 function prototypes copied from ha_innodb.cc: */
-
-/*****************************************************************
-If you want to print a thd that is not associated with the current thread,
-you must call this function before reserving the InnoDB kernel_mutex, to
-protect MySQL from setting thd->query NULL. If you print a thd of the current
-thread, we know that MySQL cannot modify thd->query, and it is not necessary
-to call this. Call innobase_mysql_end_print_arbitrary_thd() after you release
-the kernel_mutex.
-NOTE that /mysql/innobase/lock/lock0lock.c must contain the prototype for this
-function! */
-
-void
-innobase_mysql_prepare_print_arbitrary_thd(void);
-/*============================================*/
-
-/*****************************************************************
-Relases the mutex reserved by innobase_mysql_prepare_print_arbitrary_thd().
-NOTE that /mysql/innobase/lock/lock0lock.c must contain the prototype for this
-function! */
-
-void
-innobase_mysql_end_print_arbitrary_thd(void);
-/*========================================*/
-
 /* Restricts the length of search we will do in the waits-for
 graph of transactions */
 #define LOCK_MAX_N_STEPS_IN_DEADLOCK_CHECK 1000000
@@ -4222,11 +4197,6 @@ lock_print_info_summary(
 /*====================*/
 	FILE*	file)	/* in: file where to print */
 {
-	/* We must protect the MySQL thd->query field with a MySQL mutex, and
-	because the MySQL mutex must be reserved before the kernel_mutex of
-	InnoDB, we call innobase_mysql_prepare_print_arbitrary_thd() here. */
-
-	innobase_mysql_prepare_print_arbitrary_thd();
 	lock_mutex_enter_kernel();
 
 	if (lock_deadlock_found) {
@@ -4314,7 +4284,6 @@ loop:
 
 	if (trx == NULL) {
 		lock_mutex_exit_kernel();
-		innobase_mysql_end_print_arbitrary_thd();
 
 		ut_ad(lock_validate());
 
@@ -4386,7 +4355,6 @@ loop:
 
 		if (load_page_first) {
 			lock_mutex_exit_kernel();
-			innobase_mysql_end_print_arbitrary_thd();
 
 			mtr_start(&mtr);
 
@@ -4397,7 +4365,6 @@ loop:
 
 			load_page_first = FALSE;
 
-			innobase_mysql_prepare_print_arbitrary_thd();
 			lock_mutex_enter_kernel();
 
 			goto loop;

storage/innobase/trx/trx0trx.c

@@ -1652,9 +1652,7 @@ trx_mark_sql_stat_end(
 
 /**************************************************************************
 Prints info about a transaction to the given file. The caller must own the
-kernel mutex and must have called
-innobase_mysql_prepare_print_arbitrary_thd(), unless he knows that MySQL
-or InnoDB cannot meanwhile change the info printed here. */
+kernel mutex. */
 
 void
 trx_print(

storage/innodb_plugin/handler/ha_innodb.cc

@@ -898,36 +898,6 @@ convert_error_code_to_mysql(
 	}
 }
 
-/*************************************************************//**
-If you want to print a thd that is not associated with the current thread,
-you must call this function before reserving the InnoDB kernel_mutex, to
-protect MySQL from setting thd->query NULL. If you print a thd of the current
-thread, we know that MySQL cannot modify thd->query, and it is not necessary
-to call this. Call innobase_mysql_end_print_arbitrary_thd() after you release
-the kernel_mutex. */
-extern "C" UNIV_INTERN
-void
-innobase_mysql_prepare_print_arbitrary_thd(void)
-/*============================================*/
-{
-	ut_ad(!mutex_own(&kernel_mutex));
-	VOID(pthread_mutex_lock(&LOCK_thread_count));
-}
-
-/*************************************************************//**
-Releases the mutex reserved by innobase_mysql_prepare_print_arbitrary_thd().
-In the InnoDB latching order, the mutex sits right above the
-kernel_mutex.  In debug builds, we assert that the kernel_mutex is
-released before this function is invoked. */
-extern "C" UNIV_INTERN
-void
-innobase_mysql_end_print_arbitrary_thd(void)
-/*========================================*/
-{
-	ut_ad(!mutex_own(&kernel_mutex));
-	VOID(pthread_mutex_unlock(&LOCK_thread_count));
-}
-
 /*************************************************************//**
 Prints info of a THD object (== user session thread) to the given file. */
 extern "C" UNIV_INTERN

storage/innodb_plugin/include/ha_prototypes.h

@@ -153,28 +153,6 @@ get_innobase_type_from_mysql_type(
 	const void*	field)		/*!< in: MySQL Field */
 	__attribute__((nonnull));
 
-/*************************************************************//**
-If you want to print a thd that is not associated with the current thread,
-you must call this function before reserving the InnoDB kernel_mutex, to
-protect MySQL from setting thd->query NULL. If you print a thd of the current
-thread, we know that MySQL cannot modify thd->query, and it is not necessary
-to call this. Call innobase_mysql_end_print_arbitrary_thd() after you release
-the kernel_mutex. */
-UNIV_INTERN
-void
-innobase_mysql_prepare_print_arbitrary_thd(void);
-/*============================================*/
-
-/*************************************************************//**
-Releases the mutex reserved by innobase_mysql_prepare_print_arbitrary_thd().
-In the InnoDB latching order, the mutex sits right above the
-kernel_mutex.  In debug builds, we assert that the kernel_mutex is
-released before this function is invoked. */
-UNIV_INTERN
-void
-innobase_mysql_end_print_arbitrary_thd(void);
-/*========================================*/
-
 /******************************************************************//**
 Get the variable length bounds of the given character set. */
 UNIV_INTERN

storage/innodb_plugin/include/trx0trx.h

@@ -338,9 +338,7 @@ trx_commit_step(
 
 /**********************************************************************//**
 Prints info about a transaction to the given file. The caller must own the
-kernel mutex and must have called
-innobase_mysql_prepare_print_arbitrary_thd(), unless he knows that MySQL
-or InnoDB cannot meanwhile change the info printed here. */
+kernel mutex. */
 UNIV_INTERN
 void
 trx_print(

storage/innodb_plugin/lock/lock0lock.c

@@ -4324,11 +4324,6 @@ lock_print_info_summary(
 /*====================*/
 	FILE*	file)	/*!< in: file where to print */
 {
-	/* We must protect the MySQL thd->query field with a MySQL mutex, and
-	because the MySQL mutex must be reserved before the kernel_mutex of
-	InnoDB, we call innobase_mysql_prepare_print_arbitrary_thd() here. */
-
-	innobase_mysql_prepare_print_arbitrary_thd();
 	lock_mutex_enter_kernel();
 
 	if (lock_deadlock_found) {
@@ -4411,7 +4406,6 @@ loop:
 
 	if (trx == NULL) {
 		lock_mutex_exit_kernel();
-		innobase_mysql_end_print_arbitrary_thd();
 
 		ut_ad(lock_validate());
 
@@ -4495,7 +4489,6 @@ loop:
 			}
 
 			lock_mutex_exit_kernel();
-			innobase_mysql_end_print_arbitrary_thd();
 
 			mtr_start(&mtr);
 
@@ -4506,7 +4499,6 @@ loop:
 
 			load_page_first = FALSE;
 
-			innobase_mysql_prepare_print_arbitrary_thd();
 			lock_mutex_enter_kernel();
 
 			goto loop;

storage/innodb_plugin/trx/trx0i_s.c

@@ -1205,9 +1205,6 @@ trx_i_s_possibly_fetch_data_into_cache(
 		return(1);
 	}
 
-	/* We are going to access trx->query in all transactions */
-	innobase_mysql_prepare_print_arbitrary_thd();
-
 	/* We need to read trx_sys and record/table lock queues */
 	mutex_enter(&kernel_mutex);
 
@@ -1215,8 +1212,6 @@ trx_i_s_possibly_fetch_data_into_cache(
 
 	mutex_exit(&kernel_mutex);
 
-	innobase_mysql_end_print_arbitrary_thd();
-
 	return(0);
 }
 

storage/innodb_plugin/trx/trx0trx.c

@@ -1636,9 +1636,7 @@ trx_mark_sql_stat_end(
 
 /**********************************************************************//**
 Prints info about a transaction to the given file. The caller must own the
-kernel mutex and must have called
-innobase_mysql_prepare_print_arbitrary_thd(), unless he knows that MySQL
-or InnoDB cannot meanwhile change the info printed here. */
+kernel mutex. */
 UNIV_INTERN
 void
 trx_print(