Server is crashing when we grant privileges to user with PAM plugin

[Ramesh Sivaraman]

** Testcase

INSTALL PLUGIN auth_pam SONAME 'auth_pam.so';
create user test_pam@localhost;
GRANT ALL PRIVILEGES ON *.* TO test_pam@localhost IDENTIFIED WITH auth_pam;

** GDB info

(gdb) bt
#0 __pthread_kill (threadid=<optimized out>, signo=11) at ../sysdeps/unix/sysv/linux/pthread_kill.c:62
#1 0x00000000007a02f4 in handle_fatal_signal (sig=11) at /sda/percona-server_opt/sql/signal_handler.cc:223
#2 <signal handler called>
#3 0x0000000000000000 in ?? ()
#4 0x00000000007c66ba in set_and_validate_user_attributes (thd=0x7fa9e6816000, Str=0x7fa9e6828a10, what_to_set=@0x7faa9833d4f8: 2,
    is_privileged_user=true) at /sda/percona-server_opt/sql/auth/sql_user.cc:537
#5 0x00000000007be48e in mysql_grant (thd=0x7fa9e6816000, db=0x0, list=..., rights=536869887, revoke_grant=false, is_proxy=false)
    at /sda/percona-server_opt/sql/auth/sql_authorization.cc:1929
#6 0x0000000000cd3177 in mysql_execute_command (thd=0x7fa9e6816000, first_level=true) at /sda/percona-server_opt/sql/sql_parse.cc:4105
#7 0x0000000000cd4b55 in mysql_parse (thd=0x7fa9e6816000, parser_state=<optimized out>) at /sda/percona-server_opt/sql/sql_parse.cc:5635
#8 0x0000000000cd5de5 in dispatch_command (thd=0x7fa9e6816000, com_data=0x7faa9833eda0, command=COM_QUERY)
    at /sda/percona-server_opt/sql/sql_parse.cc:1304
#9 0x0000000000cd68e4 in do_command (thd=0x7fa9e6816000) at /sda/percona-server_opt/sql/sql_parse.cc:867
#10 0x0000000000da9e4c in handle_connection (arg=<optimized out>) at /sda/percona-server_opt/sql/conn_handler/connection_handler_per_thread.cc:307
#11 0x000000000119ca24 in pfs_spawn_thread (arg=0x7faa8d3b9320) at /sda/percona-server_opt/storage/perfschema/pfs.cc:2192
#12 0x00007faa97d516aa in start_thread (arg=0x7faa9833f700) at pthread_create.c:333
#13 0x00007faa9699feed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109
(gdb)

[Sergei Glushchenko (sergei.glushchenko)]

https://github.com/percona/percona-server/pull/278

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-3334