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I have Ubuntu 12.04 running MySQL server 5.5.24. I can connect with mysql --user root -p. status shows me :

Connection: Localhost via UNIX socket

When I try to connect with mysql --host --user root -p (or with --protocol=tcp) I can connect (get a prompt) but anything I'll try to do will get me this error:

ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    39
Current database: *** NONE ***

ERROR 2013 (HY000): Lost connection to MySQL server during query

netstat -pal | grep -P '3306|mysql' shows:

tcp        0      0 localhost:mysql         *:*                     LISTEN      26535/mysqld    
unix  2      [ ACC ]     STREAM     LISTENING     121787   26535/mysqld        /var/run/mysqld/mysqld.sock
unix  3      [ ]         STREAM     CONNECTED     18810    2252/mysql-workbenc 
unix  3      [ ]         STREAM     CONNECTED     16377    2252/mysql-workbenc 
unix  3      [ ]         STREAM     CONNECTED     18765    2252/mysql-workbenc 
unix  3      [ ]         STREAM     CONNECTED     17959    2252/mysql-workbenc 

Using UNIX sockets I'm able to work just fine. Any ideas?

EDIT - my /etc/mysql/my.cnf

# The MySQL database server configuration file.
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
# For explanations see

# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# Remember to edit /etc/mysql/debian.cnf when changing the socket location.
port        = 3306
socket      = /var/run/mysqld/mysqld.sock

# Here is entries for some specific programs
# The following values assume you have at least 32M ram

# This was formally known as [safe_mysqld]. Both versions are currently parsed.
socket      = /var/run/mysqld/mysqld.sock
nice        = 0

# * Basic Settings
user        = mysql
pid-file    = /var/run/mysqld/
socket      = /var/run/mysqld/mysqld.sock
port        = 3306
basedir     = /usr
datadir     = /var/lib/mysql
tmpdir      = /tmp
lc-messages-dir = /usr/share/mysql
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address        =
# * Fine Tuning
key_buffer      = 16M
max_allowed_packet  = 16M
thread_stack        = 192K
thread_cache_size       = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover         = BACKUP
#max_connections        = 100
#table_cache            = 64
#thread_concurrency     = 10
# * Query Cache Configuration
query_cache_limit   = 1M
query_cache_size        = 16M
# * Logging and Replication
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file        = /var/log/mysql/mysql.log
#general_log             = 1
# Error logging goes to syslog due to /etc/mysql/conf.d/mysqld_safe_syslog.cnf.
# Here you can see queries with especially long duration
#log_slow_queries   = /var/log/mysql/mysql-slow.log
#long_query_time = 2
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
#       other settings you may need to change.
#server-id      = 1
#log_bin            = /var/log/mysql/mysql-bin.log
expire_logs_days    = 10
max_binlog_size         = 100M
#binlog_do_db       = include_database_name
#binlog_ignore_db   = include_database_name
# * InnoDB
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
# * Security Features
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem

max_allowed_packet  = 16M

#no-auto-rehash # faster start of mysql but no tab completition

key_buffer      = 16M

# * IMPORTANT: Additional settings that can override those from this file!
#   The files must end with '.cnf', otherwise they'll be ignored.
!includedir /etc/mysql/conf.d/

EDIT - New findings

I just found out that the mysqld process crashes every time I'm trying to connect with tcp and run something. I see that in /var/log/syslog and used ps -ef to verify that the PID changes:

Oct 24 16:14:47 desktop kernel: [13190.117685] init: mysql main process (27929) terminated with status 1
Oct 24 16:14:47 desktop kernel: [13190.117685] init: mysql main process ended, respawning
Oct 24 16:14:48 desktop kernel: [13190.212097] type=1400 audit(1351088088.044:124): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/mysqld" pid=28079 comm="apparmor_parser"
Oct 24 16:14:50 desktop /etc/mysql/debian-start[28123]: Upgrading MySQL tables if necessary.
Oct 24 16:14:50 desktop /etc/mysql/debian-start[28126]: /usr/bin/mysql_upgrade: the '--basedir' option is always ignored
Oct 24 16:14:50 desktop /etc/mysql/debian-start[28126]: Looking for 'mysql' as: /usr/bin/mysql
Oct 24 16:14:50 desktop /etc/mysql/debian-start[28126]: Looking for 'mysqlcheck' as: /usr/bin/mysqlcheck
Oct 24 16:14:50 desktop /etc/mysql/debian-start[28126]: This installation of MySQL is already upgraded to 5.5.24, use --force if you still need to run mysql_upgrade
Oct 24 16:14:50 desktop /etc/mysql/debian-start[28137]: Checking for insecure root accounts.
Oct 24 16:14:50 desktop /etc/mysql/debian-start[28142]: Triggering myisam-recover for all MyISAM tables

This is pretty much like the regular log when I start mysqld but I posted it anyway in case someone get something interesting out of it.

EDIT: my /etc/apparmor.d/usr.sbin.mysqld

# vim:syntax=apparmor
# Last Modified: Tue Jun 19 17:37:30 2007
#include <tunables/global>

/usr/sbin/mysqld {
  #include <abstractions/base>
  #include <abstractions/nameservice>
  #include <abstractions/user-tmp>
  #include <abstractions/mysql>
  #include <abstractions/winbind>

  capability dac_override,
  capability sys_resource,
  capability setgid,
  capability setuid,

  network tcp,

  /etc/hosts.allow r,
  /etc/hosts.deny r,

  /etc/mysql/*.pem r,
  /etc/mysql/conf.d/ r,
  /etc/mysql/conf.d/* r,
  /etc/mysql/*.cnf r,
  /usr/lib/mysql/plugin/ r,
  /usr/lib/mysql/plugin/*.so* mr,
  /usr/sbin/mysqld mr,
  /usr/share/mysql/** r,
  /var/log/mysql.log rw,
  /var/log/mysql.err rw,
  /var/lib/mysql/ r,
  /var/lib/mysql/** rwk,
  /var/log/mysql/ r,
  /var/log/mysql/* rw,
  /var/run/mysqld/ w,
  /var/run/mysqld/mysqld.sock w,
  /run/mysqld/ w,
  /run/mysqld/mysqld.sock w,

  /sys/devices/system/cpu/ r,

  # Site-specific additions and overrides. See local/README for details.
  #include <local/usr.sbin.mysqld>

EDIT - The stacktrace of mysqld when it crashes

I run mysqld from commandline and then connected from other console. The server crashes immediately when I connect with this output:

121024 16:59:09 [Note] mysqld: ready for connections.
Version: '5.5.24-0ubuntu0.12.04.1'  socket: '/var/run/mysqld/mysqld.sock'  port: 3306  (Ubuntu)
14:59:37 UTC - mysqld got signal 8 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed, 
something is definitely wrong and this may fail.

It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 346679 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x7fd27a8ccb10
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 7fd277befe60 thread_stack 0x30000

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (0): is an invalid pointer
Connection ID (thread ID): 2

The manual page at contains
information that should help you find out what is causing the crash.

It says something about memory usage (~350MB), so it might be relevant to know that the sever is virtual (VBox under windows 7 machine) with 5GB RAM (out of 8GB at the host). I checked and there are 3.5GB free on the guest machine.

share|improve this question
Post your my.cnf. – pkhamre Oct 24 '12 at 13:42
thanks @pkhamre - added that. – Zach Moshe Oct 24 '12 at 13:56
This seems to be an apparmor issue, can you please post /etc/apparmor.d/usr.sbin.mysqld too? – Hex Oct 24 '12 at 14:44
@Hex - thanks. added that too. – Zach Moshe Oct 24 '12 at 14:50
can you "sudo /etc/init.d/apparmor kill" and restart mysql? – Hex Oct 24 '12 at 14:58

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