Use normal mutex for rw_lock_debug_mutexbb-10.5-MDEV-24167

3 files changed, 7 insertions, 25 deletions

diff --git a/storage/innobase/include/sync0debug.h b/storage/innobase/include/sync0debug.h
index 07e985465e0..da3feecfa53 100644
--- a/storage/innobase/include/sync0debug.h
+++ b/storage/innobase/include/sync0debug.h
@@ -84,11 +84,7 @@ Terminate iteration if the functor returns true.
 bool
 sync_check_iterate(const sync_check_functor_t& functor);
 
-/** Acquires the debug mutex. We cannot use the mutex defined in sync0sync,
-because the debug mutex is also acquired in sync0arr while holding the OS
-mutex protecting the sync array, and the ordinary mutex_enter might
-recursively call routines in sync0arr, leading to a deadlock on the OS
-mutex. */
+/** Acquires the debug mutex. */
 void
 rw_lock_debug_mutex_enter();
 
diff --git a/storage/innobase/include/sync0types.h b/storage/innobase/include/sync0types.h
index a40040f31e5..45ca2f4dfe3 100644
--- a/storage/innobase/include/sync0types.h
+++ b/storage/innobase/include/sync0types.h
@@ -252,7 +252,6 @@ enum latch_id_t {
 	LATCH_ID_RECALC_POOL,
 	LATCH_ID_REDO_RSEG,
 	LATCH_ID_NOREDO_RSEG,
-	LATCH_ID_RW_LOCK_DEBUG,
 	LATCH_ID_RTR_ACTIVE_MUTEX,
 	LATCH_ID_RTR_MATCH_MUTEX,
 	LATCH_ID_RTR_PATH_MUTEX,
diff --git a/storage/innobase/sync/sync0debug.cc b/storage/innobase/sync/sync0debug.cc
index 2748929c1eb..a266e1a283a 100644
--- a/storage/innobase/sync/sync0debug.cc
+++ b/storage/innobase/sync/sync0debug.cc
@@ -47,7 +47,7 @@ my_bool		srv_sync_debug;
 /** The global mutex which protects debug info lists of all rw-locks.
 To modify the debug info list of an rw-lock, this mutex has to be
 acquired in addition to the mutex protecting the lock. */
-static SysMutex		rw_lock_debug_mutex;
+static mysql_mutex_t rw_lock_debug_mutex;
 
 /** The latch held by a thread */
 struct Latched {
@@ -1105,7 +1105,7 @@ void
 LatchDebug::init()
 	UNIV_NOTHROW
 {
-	mutex_create(LATCH_ID_RW_LOCK_DEBUG, &rw_lock_debug_mutex);
+  mysql_mutex_init(rw_lock_debug_mutex_key, &rw_lock_debug_mutex, nullptr);
 }
 
 /** Shutdown the latch debug checking
@@ -1116,7 +1116,7 @@ void
 LatchDebug::shutdown()
 	UNIV_NOTHROW
 {
-	mutex_free(&rw_lock_debug_mutex);
+	mysql_mutex_destroy(&rw_lock_debug_mutex);
 
 	ut_a(s_initialized);
 
@@ -1127,22 +1127,18 @@ LatchDebug::shutdown()
 	LatchDebug::s_instance = NULL;
 }
 
-/** Acquires the debug mutex. We cannot use the mutex defined in sync0sync,
-because the debug mutex is also acquired in sync0arr while holding the OS
-mutex protecting the sync array, and the ordinary mutex_enter might
-recursively call routines in sync0arr, leading to a deadlock on the OS
-mutex. */
+/** Acquires the debug mutex. */
 void
 rw_lock_debug_mutex_enter()
 {
-	mutex_enter(&rw_lock_debug_mutex);
+	mysql_mutex_lock(&rw_lock_debug_mutex);
 }
 
 /** Releases the debug mutex. */
 void
 rw_lock_debug_mutex_exit()
 {
-	mutex_exit(&rw_lock_debug_mutex);
+	mysql_mutex_unlock(&rw_lock_debug_mutex);
 }
 #endif /* UNIV_DEBUG */
 
@@ -1186,15 +1182,6 @@ sync_latch_meta_init()
 
 	LATCH_ADD_MUTEX(NOREDO_RSEG, SYNC_NOREDO_RSEG, noredo_rseg_mutex_key);
 
-#ifdef UNIV_DEBUG
-	/* Mutex names starting with '.' are not tracked. They are assumed
-	to be diagnostic mutexes used in debugging. */
-	latch_meta[LATCH_ID_RW_LOCK_DEBUG] =
-		LATCH_ADD_MUTEX(RW_LOCK_DEBUG,
-			SYNC_NO_ORDER_CHECK,
-			rw_lock_debug_mutex_key);
-#endif /* UNIV_DEBUG */
-
 	LATCH_ADD_MUTEX(RTR_ACTIVE_MUTEX, SYNC_ANY_LATCH,
 			rtr_active_mutex_key);