diff --git a/cmake/cpack_rpm.cmake b/cmake/cpack_rpm.cmake
index 7fb0be23f02..1d86660e5e0 100644
--- a/cmake/cpack_rpm.cmake
+++ b/cmake/cpack_rpm.cmake
@@ -298,6 +298,7 @@ ENDIF()
 # MDEV-24629, we need it outside of ELSIFs
 IF(RPM MATCHES "fedora")
   ALTERNATIVE_NAME("common" "mariadb-connector-c-config" ${MARIADB_CONNECTOR_C_VERSION}-1)
+  ALTERNATIVE_NAME("shared" "mariadb-connector-c" ${MARIADB_CONNECTOR_C_VERSION}-1)
 ENDIF()
 
 SET(PYTHON_SHEBANG "/usr/bin/python3" CACHE STRING "python shebang")
diff --git a/mysql-test/main/sp-memory-leak.result b/mysql-test/main/sp-memory-leak.result
new file mode 100644
index 00000000000..37a0f119341
--- /dev/null
+++ b/mysql-test/main/sp-memory-leak.result
@@ -0,0 +1,42 @@
+#
+# MDEV-30680 Warning: Memory not freed: 280 on mangled query, LeakSanitizer: detected memory leaks
+#
+BEGIN NOT ATOMIC
+IF SCALAR() expected_THEN_here;
+END
+$$
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'expected_THEN_here;
+END' at line 2
+BEGIN NOT ATOMIC
+WHILE SCALAR() expected_DO_here;
+END
+$$
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'expected_DO_here;
+END' at line 2
+BEGIN NOT ATOMIC
+REPEAT SELECT 1; UNTIL SCALAR() expected_END_here;
+END
+$$
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'expected_END_here;
+END' at line 2
+#
+# MDEV-31578 DECLARE CURSOR: "Memory not freed: 280 bytes lost" on syntax error
+#
+BEGIN NOT ATOMIC
+DECLARE cur CURSOR (a INT) FOR SELECT a+1;
+OPEN cur(sp_followed_by_syntax_error();
+CLOSE cur;
+END;
+$$
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ';
+CLOSE cur;
+END' at line 3
+BEGIN NOT ATOMIC
+DECLARE cur CURSOR (a INT) FOR SELECT a+1;
+OPEN cur(1,sp_followed_by_syntax_error();
+CLOSE cur;
+END;
+$$
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ';
+CLOSE cur;
+END' at line 3
diff --git a/mysql-test/main/sp-memory-leak.test b/mysql-test/main/sp-memory-leak.test
new file mode 100644
index 00000000000..0035044209a
--- /dev/null
+++ b/mysql-test/main/sp-memory-leak.test
@@ -0,0 +1,54 @@
+--echo #
+--echo # MDEV-30680 Warning: Memory not freed: 280 on mangled query, LeakSanitizer: detected memory leaks
+--echo #
+
+DELIMITER $$;
+--error ER_PARSE_ERROR
+BEGIN NOT ATOMIC
+  IF SCALAR() expected_THEN_here;
+END
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+--error ER_PARSE_ERROR
+BEGIN NOT ATOMIC
+  WHILE SCALAR() expected_DO_here;
+END
+$$
+DELIMITER ;$$
+
+
+DELIMITER $$;
+--error ER_PARSE_ERROR
+BEGIN NOT ATOMIC
+  REPEAT SELECT 1; UNTIL SCALAR() expected_END_here;
+END
+$$
+DELIMITER ;$$
+
+
+--echo #
+--echo # MDEV-31578 DECLARE CURSOR: "Memory not freed: 280 bytes lost" on syntax error
+--echo #
+
+DELIMITER $$;
+--error ER_PARSE_ERROR
+BEGIN NOT ATOMIC
+  DECLARE cur CURSOR (a INT) FOR SELECT a+1;
+  OPEN cur(sp_followed_by_syntax_error();
+  CLOSE cur;
+END;
+$$
+DELIMITER ;$$
+
+DELIMITER $$;
+--error ER_PARSE_ERROR
+BEGIN NOT ATOMIC
+  DECLARE cur CURSOR (a INT) FOR SELECT a+1;
+  OPEN cur(1,sp_followed_by_syntax_error();
+  CLOSE cur;
+END;
+$$
+DELIMITER ;$$
diff --git a/sql/sp_head.h b/sql/sp_head.h
index 57def5baa83..177fb5d233d 100644
--- a/sql/sp_head.h
+++ b/sql/sp_head.h
@@ -608,20 +608,24 @@ public:
   restore_lex(THD *thd)
   {
     DBUG_ENTER("sp_head::restore_lex");
+    /*
+      There is no a need to free the current thd->lex here.
+      - In the majority of the cases restore_lex() is called
+        on success and thd->lex does not need to be deleted.
+      - In cases when restore_lex() is called on error,
+        e.g. from sp_create_assignment_instr(), thd->lex is
+        already linked to some sp_instr_xxx (using sp_lex_keeper).
+
+      Note, we don't get to here in case of a syntax error
+      when the current thd->lex is not yet completely
+      initialized and linked. It gets automatically deleted
+      by the Bison %destructor in sql_yacc.yy.
+    */
     LEX *oldlex= (LEX *) m_lex.pop();
     if (!oldlex)
       DBUG_RETURN(false); // Nothing to restore
-    LEX *sublex= thd->lex;
     // This restores thd->lex and thd->stmt_lex
-    if (thd->restore_from_local_lex_to_old_lex(oldlex))
-      DBUG_RETURN(true);
-    if (!sublex->sp_lex_in_use)
-    {
-      sublex->sphead= NULL;
-      lex_end(sublex);
-      delete sublex;
-    }
-    DBUG_RETURN(false);
+    DBUG_RETURN(thd->restore_from_local_lex_to_old_lex(oldlex));
   }
 
   /**
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 5967a4a452a..d152eb8eeb8 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -486,11 +486,15 @@ bool sp_create_assignment_instr(THD *thd, bool no_lookahead,
         be deleted by the destructor ~sp_instr_xxx().
         So we should remove "lex" from the stack sp_head::m_lex,
         to avoid double free.
-        Note, in case "lex" is not owned by any sp_instr_xxx,
-        it's also safe to remove it from the stack right now.
-        So we can remove it unconditionally, without testing lex->sp_lex_in_use.
       */
       lex->sphead->restore_lex(thd);
+      /*
+        No needs for "delete lex" here: "lex" is already linked
+        to the sp_instr_stmt (using sp_lex_keeper) instance created by
+        the call for new_sp_instr_stmt() above. It will be freed
+        by ~sp_head/~sp_instr/~sp_lex_keeper during THD::end_statement().
+      */
+      DBUG_ASSERT(lex->sp_lex_in_use); // used by sp_instr_stmt
       return true;
     }
     enum_var_type inner_option_type= lex->option_type;
@@ -6843,7 +6847,6 @@ bool LEX::sp_for_loop_implicit_cursor_statement(THD *thd,
   if (unlikely(!(bounds->m_index=
                  new (thd->mem_root) sp_assignment_lex(thd, this))))
     return true;
-  bounds->m_index->sp_lex_in_use= true;
   sphead->reset_lex(thd, bounds->m_index);
   DBUG_ASSERT(thd->lex != this);
   /*
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 24185dbc734..a7384967ce7 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -3474,6 +3474,12 @@ public:
   sp_head *sphead;
   sp_name *spname;
 
+  void delete_if_not_sp_lex_in_use()
+  {
+    if (!sp_lex_in_use)
+      delete this;
+  }
+
   sp_pcontext *spcont;
 
   st_sp_chistics sp_chistics;
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 8a8b4306921..655dde315aa 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -10399,6 +10399,15 @@ bool parse_sql(THD *thd, Parser_state *parser_state,
 
   bool mysql_parse_status= thd->variables.sql_mode & MODE_ORACLE
                            ? ORAparse(thd) : MYSQLparse(thd);
+
+  if (mysql_parse_status)
+    /*
+      Restore the original LEX if it was replaced when parsing
+      a stored procedure. We must ensure that a parsing error
+      does not leave any side effects in the THD.
+    */
+    LEX::cleanup_lex_after_parse_error(thd);
+
   DBUG_ASSERT(opt_bootstrap || mysql_parse_status ||
               thd->lex->select_stack_top == 0);
   thd->lex->current_select= thd->lex->first_select_lex();
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 062b6366246..6a2f8f0d459 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -99,7 +99,6 @@ int yylex(void *yylval, void *yythd);
 #define MYSQL_YYABORT                         \
   do                                          \
   {                                           \
-    LEX::cleanup_lex_after_parse_error(thd);  \
     YYABORT;                                  \
   } while (0)
 
@@ -150,13 +149,6 @@ static Item* escape(THD *thd)
 
 static void yyerror(THD *thd, const char *s)
 {
-  /*
-    Restore the original LEX if it was replaced when parsing
-    a stored procedure. We must ensure that a parsing error
-    does not leave any side effects in the THD.
-  */
-  LEX::cleanup_lex_after_parse_error(thd);
-
   /* "parse error" changed into "syntax error" between bison 1.75 and 1.875 */
   if (strcmp(s,"parse error") == 0 || strcmp(s,"syntax error") == 0)
     s= ER_THD(thd, ER_SYNTAX_ERROR);
@@ -1542,6 +1534,19 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %type <expr_lex>
         expr_lex
 
+%destructor
+{
+  /*
+     In case of a syntax/oom error let's free the sp_expr_lex
+     instance, but only if it has not been linked to any structures
+     such as sp_instr_jump_if_not::m_lex_keeper yet, e.g.:
+       IF f1() THEN1
+     i.e. THEN1 came instead of the expected THEN causing a syntax error.
+  */
+  if (!$$->sp_lex_in_use)
+    delete $$;
+} <expr_lex>
+
 %type <assignment_lex>
         assignment_source_lex
         assignment_source_expr
@@ -1551,6 +1556,21 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
         cursor_actual_parameters
         opt_parenthesized_cursor_actual_parameters
 
+%destructor
+{
+  if ($$)
+  {
+    sp_assignment_lex *elem;
+    List_iterator<sp_assignment_lex> li(*$$);
+    while ((elem= li++))
+    {
+      if (!elem->sp_lex_in_use)
+        delete elem;
+    }
+  }
+} <sp_assignment_lex_list>
+
+
 %type <var_type>
         option_type opt_var_type opt_var_ident_type
 
@@ -3832,7 +3852,6 @@ expr_lex:
           expr
           {
             $$= $<expr_lex>1;
-            $$->sp_lex_in_use= true;
             $$->set_item($2);
             Lex->pop_select(); //min select
             if (Lex->check_cte_dependencies_and_resolve_references())
@@ -3864,7 +3883,6 @@ assignment_source_expr:
           {
             DBUG_ASSERT($1 == thd->lex);
             $$= $1;
-            $$->sp_lex_in_use= true;
             $$->set_item_and_free_list($3, thd->free_list);
             thd->free_list= NULL;
             Lex->pop_select(); //min select
@@ -3885,7 +3903,6 @@ for_loop_bound_expr:
           {
             DBUG_ASSERT($1 == thd->lex);
             $$= $1;
-            $$->sp_lex_in_use= true;
             $$->set_item_and_free_list($3, NULL);
             Lex->pop_select(); //main select
             if (unlikely($$->sphead->restore_lex(thd)))
diff --git a/storage/innobase/fil/fil0fil.cc b/storage/innobase/fil/fil0fil.cc
index e08d8a25171..272de85a775 100644
--- a/storage/innobase/fil/fil0fil.cc
+++ b/storage/innobase/fil/fil0fil.cc
@@ -378,8 +378,16 @@ static bool fil_node_open_file_low(fil_node_t *node)
                                  : OS_FILE_OPEN | OS_FILE_ON_ERROR_NO_EXIT,
                                  OS_FILE_AIO, type,
                                  srv_read_only_mode, &success);
-    if (success)
+    if (node->is_open())
+    {
+      ut_ad(success);
+#ifndef _WIN32
+      if (!node->space->id && !srv_read_only_mode && my_disable_locking &&
+          os_file_lock(node->handle, node->name))
+        goto fail;
+#endif
       break;
+    }
 
     /* The following call prints an error message */
     if (os_file_get_last_error(true) == EMFILE + 100 &&
@@ -393,6 +401,9 @@ static bool fil_node_open_file_low(fil_node_t *node)
   if (node->size);
   else if (!node->read_page0() || !fil_comp_algo_validate(node->space))
   {
+#ifndef _WIN32
+  fail:
+#endif
     os_file_close(node->handle);
     node->handle= OS_FILE_CLOSED;
     return false;
diff --git a/storage/innobase/rem/rem0rec.cc b/storage/innobase/rem/rem0rec.cc
index 766f5000a0d..a862edd786a 100644
--- a/storage/innobase/rem/rem0rec.cc
+++ b/storage/innobase/rem/rem0rec.cc
@@ -242,9 +242,11 @@ enum rec_leaf_format {
 	REC_LEAF_INSTANT
 };
 
-#if defined __GNUC__ && !defined __clang__ && __GNUC__ < 12
+#if defined __GNUC__ && !defined __clang__
 # pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wconversion" /* GCC 5 to 11 need this */
+# if __GNUC__ < 12 || defined WITH_UBSAN
+#  pragma GCC diagnostic ignored "-Wconversion"
+# endif
 #endif
 /** Determine the offset to each field in a leaf-page record
 in ROW_FORMAT=COMPACT,DYNAMIC,COMPRESSED.
@@ -1707,7 +1709,7 @@ rec_convert_dtuple_to_rec_new(
 			    REC_INFO_BITS_MASK, REC_INFO_BITS_SHIFT);
 	return buf;
 }
-#if defined __GNUC__ && !defined __clang__ && __GNUC__ < 11
+#if defined __GNUC__ && !defined __clang__
 # pragma GCC diagnostic pop /* ignored "-Wconversion" */
 #endif
 
diff --git a/storage/spider/mysql-test/spider/bugfix/r/self_reference_multi.result b/storage/spider/mysql-test/spider/bugfix/r/self_reference_multi.result
index c4399ddf9d2..50db034c8cd 100644
--- a/storage/spider/mysql-test/spider/bugfix/r/self_reference_multi.result
+++ b/storage/spider/mysql-test/spider/bugfix/r/self_reference_multi.result
@@ -4,11 +4,11 @@ for child3
 
 MDEV-6268 SPIDER table with no COMMENT clause causes queries to wait forever
 
-CREATE SERVER srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET "$MASTER_1_MYSOCK", DATABASE 'test',user 'root');
+CREATE SERVER $srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET "$MASTER_1_MYSOCK", DATABASE 'test',user 'root');
 create table t2 (c int);
-create table t1 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t2"';
-create table t0 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t1"';
-alter table t2 ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t0"';
+create table t1 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv_self_reference_multi",TABLE "t2"';
+create table t0 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv_self_reference_multi",TABLE "t1"';
+alter table t2 ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv_self_reference_multi",TABLE "t0"';
 select * from t0;
 ERROR HY000: An infinite loop is detected when opening table test.t0
 select * from t1;
diff --git a/storage/spider/mysql-test/spider/bugfix/t/self_reference_multi.test b/storage/spider/mysql-test/spider/bugfix/t/self_reference_multi.test
index 8b6f070d167..a3d561f3fae 100644
--- a/storage/spider/mysql-test/spider/bugfix/t/self_reference_multi.test
+++ b/storage/spider/mysql-test/spider/bugfix/t/self_reference_multi.test
@@ -8,12 +8,12 @@
 --echo MDEV-6268 SPIDER table with no COMMENT clause causes queries to wait forever
 --echo
 
---replace_regex /SOCKET ".*"/SOCKET "$MASTER_1_MYSOCK"/
-eval CREATE SERVER srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET "$MASTER_1_MYSOCK", DATABASE 'test',user 'root');
+--let $srv=srv_self_reference_multi
+evalp CREATE SERVER $srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET "$MASTER_1_MYSOCK", DATABASE 'test',user 'root');
 create table t2 (c int);
-create table t1 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t2"';
-create table t0 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t1"';
-alter table t2 ENGINE=Spider COMMENT='WRAPPER "mysql", srv "srv",TABLE "t0"';
+eval create table t1 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "$srv",TABLE "t2"';
+eval create table t0 (c int) ENGINE=Spider COMMENT='WRAPPER "mysql", srv "$srv",TABLE "t1"';
+eval alter table t2 ENGINE=Spider COMMENT='WRAPPER "mysql", srv "$srv",TABLE "t0"';
 --error 12719
 select * from t0;
 --error 12719