Ubuntu 14.04
Linux 3.13.0-30-generic #55-Ubuntu SMP Fri Jul 4 21:40:53 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
mysql  Ver 14.14 Distrib 5.6.19-67.0, for debian-linux-gnu (x86_64) using  EditLine wrapper

2014-08-28 12:42:52 7f69dc4f2700  InnoDB: Assertion failure in thread 140092644468480 in file lock0lock.cc line 3980
InnoDB: Failing assertion: lock != ctx->wait_lock

key_buffer_size=8388608
read_buffer_size=131072
max_used_connections=18
max_threads=502
thread_count=25
connection_count=8
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 208561 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x7f6ab3ae2a40
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 = 7f69dc4f1e00 thread_stack 0x40000
/usr/sbin/mysqld(my_print_stacktrace+0x2c)[0x7f6aae4b904c]
/usr/sbin/mysqld(handle_fatal_signal+0x3cb)[0x7f6aae1ffa2b]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x10340)[0x7f6aac6aa340]
/lib/x86_64-linux-gnu/libc.so.6(gsignal+0x39)[0x7f6aabaeaf79]
/lib/x86_64-linux-gnu/libc.so.6(abort+0x148)[0x7f6aabaee388]
/usr/sbin/mysqld(+0x7ee8aa)[0x7f6aae56d8aa]
/usr/sbin/mysqld(+0x7f7107)[0x7f6aae576107]
/usr/sbin/mysqld(+0x7f869f)[0x7f6aae57769f]
/usr/sbin/mysqld(+0x7f91bd)[0x7f6aae5781bd]
/usr/sbin/mysqld(+0x7f9e4c)[0x7f6aae578e4c]
/usr/sbin/mysqld(+0x363c1d)[0x7f6aae0e2c1d]
/usr/sbin/mysqld(+0x8750e8)[0x7f6aae5f40e8]
/usr/sbin/mysqld(+0x7c1e8c)[0x7f6aae540e8c]
/usr/sbin/mysqld(_ZN7handler16read_range_firstEPK12st_key_rangeS2_bb+0x2a8)[0x7f6aae129818]
/usr/sbin/mysqld(_ZN7handler21multi_range_read_nextEPPc+0x86)[0x7f6aae127fe6]
/usr/sbin/mysqld(_ZN18QUICK_RANGE_SELECT8get_nextEv+0x4b)[0x7f6aae3b311b]
/usr/sbin/mysqld(+0x65b0cd)[0x7f6aae3da0cd]
/usr/sbin/mysqld(_Z12mysql_updateP3THDP10TABLE_LISTR4ListI4ItemES6_PS4_jP8st_ordery15enum_duplicatesbPySB_+0xe61)[0x7f6aae30c2c1]
/usr/sbin/mysqld(_Z21mysql_execute_commandP3THD+0xfad)[0x7f6aae29150d]
/usr/sbin/mysqld(+0x519ee8)[0x7f6aae298ee8]
/usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1280)[0x7f6aae29a680]
/usr/sbin/mysqld(_Z10do_commandP3THD+0x16c)[0x7f6aae29c8fc]
/usr/sbin/mysqld(_Z24do_handle_one_connectionP3THD+0x31d)[0x7f6aae25dd3d]
/usr/sbin/mysqld(handle_one_connection+0x40)[0x7f6aae25dde0]
/usr/sbin/mysqld(pfs_spawn_thread+0x140)[0x7f6aae731fb0]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x8182)[0x7f6aac6a2182]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f6aabbaf30d]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (7f6a6c0334a0): is an invalid pointer
Connection ID (thread ID): 2984679
Status: NOT_KILLED

You may download the Percona XtraDB Cluster operations manual by visiting
http://www.percona.com/software/percona-xtradb-cluster/. You may find information
in the manual which will help you identify the cause of the crash.
140828 12:42:52 mysqld_safe Number of processes running now: 0
140828 12:42:52 mysqld_safe WSREP: not restarting wsrep node automatically
140828 12:42:52 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended