innobackupex crashing Percona server 5.6.21-70.1

Running a backup on a node of a cluster using innobackupex v2.2.8. The backup fails with the following:

150212 15:49:05 innobackupex: Finished backing up non-InnoDB tables and files

150212 15:49:05 innobackupex: Executing LOCK BINLOG FOR BACKUP...
DBD::mysql::db do failed: Deadlock found when trying to get lock; try restarting transaction at /usr/bin/innobackupex line 3036.
innobackupex: got a fatal error with the following stacktrace: at /usr/bin/innobackupex line 3039
main::mysql_query('HASH(0x1adbda0)', 'LOCK BINLOG FOR BACKUP') called at /usr/bin/innobackupex line 3501
main::mysql_lock_binlog('HASH(0x1adbda0)') called at /usr/bin/innobackupex line 2000
main::backup() called at /usr/bin/innobackupex line 1592
innobackupex: Error: 
Error executing 'LOCK BINLOG FOR BACKUP': DBD::mysql::db do failed: Deadlock found when trying to get lock; try restarting transaction at /usr/bin/innobackupex line 3036.
150212 15:49:05 innobackupex: Waiting for ibbackup (pid=29318) to finish
DB Backup ending at Thu 12 Feb 2015 03:49:05 PM MST

At the same time, the mysqld process logs and exits:


22:49:05 UTC - mysqld got signal 11 ;
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.
Please help us make Percona XtraDB Cluster better by reporting any
bugs at https://bugs.launchpad.net/percona-xtradb-cluster

key_buffer_size=25165824
read_buffer_size=131072
max_used_connections=2
max_threads=202
thread_count=3
connection_count=1
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 105204 K bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x16598640
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 = 7f28bc0e5d38 thread_stack 0x40000
/usr/sbin/mysqld(my_print_stacktrace+0x35)[0x8f97d5]
/usr/sbin/mysqld(handle_fatal_signal+0x4b4)[0x6655c4]
/lib64/libpthread.so.0[0x396ec0f710]
[0x7f25200000a8]

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): 14411
Status: KILL_CONNECTION

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.

Doesn’t happen consistently.

I would think that the backup should just fail, but it shouldn’t crash the mysql server in the process. Alternately, the mysql process crashed and that caused the backup to fail, but then I would think that innobackex shouldn’t be causing the server to crash.

Any ideas on causality here?