daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: mysqld got signal 11;
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: This could be because you hit a bug. It is also possible that this binary
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: or one of the libraries it was linked against is corrupt, improperly built,
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: or misconfigured. This error can also be caused by malfunctioning hardware.
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: We will try our best to scrape up some info that will hopefully help diagnose
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: the problem, but since we have already crashed, something is definitely wrong
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: and this may fail.
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: key_buffer_size=134217728
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: read_buffer_size=2093056
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: max_used_connections=41
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: max_connections=100
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: threads_connected=11
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: It is possible that mysqld could use up to 
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 1154671 K
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: bytes of memory
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: Hope that's ok; if not, decrease some variables in the equation.
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: thd=0xa00e0b0
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: Attempting backtrace. You can use the following information to find out
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: where mysqld died. If you see no messages after this, something went
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: terribly wrong...
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: Cannot determine thread, fp=0x6c0c1d78, backtrace may not be correct.
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: Stack range sanity check OK, backtrace follows:
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0x81ba944
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0xffffe420
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0x9f028dc
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0x81d35a8
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0x8227620
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0x82263ea
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0x81ce7fd
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0x81cd37d
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0x81cc812
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0xb7edab63
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: 0xb7d5218a
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: New value of fp=(nil) failed sanity check, terminating stack trace!
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: Please read http://dev.mysql.com/doc/mysql/en/Using_stack_trace.html and follow instructions on how to resolve the stack trace. Resolved
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: stack trace is much more helpful in diagnosing the problem, so please do 
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: resolve it
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: Trying to get some variables.
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: Some pointers may be invalid and cause the dump to abort...
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: thd->query at 0x9f2b330 = DELETE FROM share_network  USING share_network,        (friends AS f         RIGHT JOIN share_network AS s         ON f.owner_username=s.username AND            f.username=s.shares_with)  WHERE share_network.username=s.username AND        share_network.shares_with=s.shares_with AND        f.owner_username IS NULL
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: thd->thread_id=46
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: The manual page at http://www.mysql.com/doc/en/Crashing.html contains
daemon.log.3:Oct  9 09:10:58 uk2-host2 mysqld[30474]: information that should help you find out what is causing the crash.