Assertion `m_lock != __null && thd->mdl_context.is_lock_owner(m_namespace, "", "", MDL_SHARED)' failed. in lock.cc:1140 | abort (sig=6) in Global_backup_lock::release

[Roel Van de Paar]

=========== Error log
mysqld: /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/lock.cc:1140: void Global_backup_lock::release(THD*): Assertion `m_lock != __null && thd->mdl_context.is_lock_owner(m_namespace, "", "", MDL_SHARED)' failed.
20:43:09 UTC - mysqld got signal 6 ;

=========== Version
Percona-Server-5.6.21-rel69.0-670.Linux.x86_64-debug

=========== Testcase
LOCK BINLOG FOR BACKUP;
lock tables performance_schema.setup_instruments write;
   ... Then shutdown server

=========== Stack
(gdb) bt
+bt
#0 0x00007fc2cedd2771 in pthread_kill () from /lib64/libpthread.so.0
#1 0x0000000000ab6f6a in my_write_core (sig=6) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/mysys/stacktrace.c:422
#2 0x000000000072f89f in handle_fatal_signal (sig=6) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/signal_handler.cc:236
#3 <signal handler called>
#4 0x00007fc2cd9d65c9 in raise () from /lib64/libc.so.6
#5 0x00007fc2cd9d7cd8 in abort () from /lib64/libc.so.6
#6 0x00007fc2cd9cf536 in __assert_fail_base () from /lib64/libc.so.6
#7 0x00007fc2cd9cf5e2 in __assert_fail () from /lib64/libc.so.6
#8 0x0000000000957420 in Global_backup_lock::release (this=0x7fc220aafa28, thd=0x7fc220aae000) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/lock.cc:1138
#9 0x0000000000796dc6 in THD::cleanup (this=0x7fc220aae000) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_class.cc:1704
#10 0x000000000079705f in THD::release_resources (this=0x7fc220aae000) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_class.cc:1771
#11 0x000000000062434c in one_thread_per_connection_end (thd=0x7fc220aae000, block_pthread=true) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/mysqld.cc:2830
#12 0x00000000007a643c in do_handle_one_connection (thd_arg=0x7fc220aae000) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_connect.cc:1546
#13 0x00000000007a5e8d in handle_one_connection (arg=0x7fc220aae000) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_connect.cc:1443
#14 0x0000000000dc5590 in pfs_spawn_thread (arg=0x7fc2b2bc9f20) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/storage/perfschema/pfs.cc:1860
#15 0x00007fc2cedcddf3 in start_thread () from /lib64/libpthread.so.0
#16 0x00007fc2cda9701d in clone () from /lib64/libc.so.6

[Roel Van de Paar (roel11)]

See bug 1360064

[Roel Van de Paar (roel11)]

This bug has testcase

Another one;
DROP DATABASE test;CREATE DATABASE test;USE test;
LOCK BINLOG FOR BACKUP;
LOCK TABLES performance_schema.setup_actors READ;
LOCK TABLE t0 WRITE;

Then exit client. If failed to crash, shutdown mysqld and it will crash.

[Roel Van de Paar (roel11)]

DROP DATABASE test;CREATE DATABASE test;USE test;
CREATE TABLE t1(c1 text,key(c1 (1))) ENGINE=innodb ROW_FORMAT=COMPACT;
FLUSH TABLES t1 FOR EXPORT;
LOCK BINLOG FOR BACKUP;
exit; // All looks fine in CLI, but check error log - mysqld crashed

Based on new testcase, can we re-triage bug to high please?

[Laurynas Biveinis (laurynas-biveinis)]

The gist of the testcase has unchanged (LBFB and then exit client).

[Roel Van de Paar (roel11)]

See bug 1371827 *

[Roel Van de Paar (roel11)]

Bug confirmed fixed (likely by patch of bug #1371827) in 5.6.24-72.2.