Comment 0 for bug 1384566

**** GDB info

+bt
#0 0x00007f8959310771 in pthread_kill () from /lib64/libpthread.so.0
#1 0x0000000000ab7586 in my_write_core (sig=11) 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 0x000000000072f9ff in handle_fatal_signal (sig=11) 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 0x000000000074ed91 in replace_user_table (thd=0x260ed40, table=0x7f8900668e60, combo=0x7f8900005190, rights=0, revoke_grant=false, can_create_user=true, no_auto_create=false) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_acl.cc:3387
#5 0x000000000075632a in mysql_grant (thd=0x260ed40, db=0x0, list=..., rights=0, revoke_grant=false, is_proxy=false) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_acl.cc:5557
#6 0x00000000007e789a in mysql_execute_command (thd=0x260ed40) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_parse.cc:4581
#7 0x00000000007ed193 in mysql_parse (thd=0x260ed40, rawbuf=0x7f89000050a0 "grant usage on *.* to usera@localhost", length=37, parser_state=0x7f8922195e30) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_parse.cc:6773
#8 0x00000000007df5fc in dispatch_command (command=COM_QUERY, thd=0x260ed40, packet=0x2601121 "grant usage on *.* to usera@localhost;", packet_length=38) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_parse.cc:1432
#9 0x00000000007de528 in do_command (thd=0x260ed40) at /mnt/workspace/percona-server-5.6-binaries-debug-yassl/label_exp/centos6-64/percona-server-5.6.21-69.0/sql/sql_parse.cc:1049
#10 0x00000000007a64e5 in do_handle_one_connection (thd_arg=0x260ed40) 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:1532
#11 0x00000000007a5fed in handle_one_connection (arg=0x260ed40) 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
#12 0x0000000000dc5bac in pfs_spawn_thread (arg=0x2dceb90) 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
#13 0x00007f895930bdf3 in start_thread () from /lib64/libpthread.so.0
#14 0x00007f8957fd501d in clone () from /lib64/libc.so.6

*** SQL info

 grant usage on *.* to usera@localhost