Code review comment for lp:~laurynas-biveinis/percona-server/bug1227581

Thread 1 (LWP 20662):
+bt
#0 0x000000363720c69c in pthread_kill () from /lib64/libpthread.so.0
#1 0x0000000000687c4e in handle_fatal_signal (sig=6) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/signal_handler.cc:254
#2 <signal handler called>
#3 0x0000003636e328a5 in raise () from /lib64/libc.so.6
#4 0x0000003636e34085 in abort () from /lib64/libc.so.6
#5 0x0000000000b91582 in buf_page_get_space (bpage=<optimized out>) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/innobase/include/buf0buf.ic:719
#6 buf_pool_get_dirty_pages_count (buf_pool=0x1eb78f8, id=84) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/innobase/buf/buf0flu.cc:2688
#7 0x0000000000b994f4 in buf_flush_dirty_pages (buf_pool=0x1eb78f8, id=84, flush=false, trx=0x0) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/innobase/buf/buf0lru.cc:728
#8 0x0000000000b9a1b8 in buf_LRU_remove_pages (trx=0x0, buf_remove=<optimized out>, id=84, buf_pool=0x1eb78f8) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/innobase/buf/buf0lru.cc:908
#9 buf_LRU_flush_or_remove_pages (id=84, buf_remove=BUF_REMOVE_FLUSH_NO_WRITE, trx=0x0) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/innobase/buf/buf0lru.cc:964
#10 0x0000000000bd6b5b in fil_delete_tablespace (id=84, buf_remove=BUF_REMOVE_FLUSH_NO_WRITE) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/innobase/fil/fil0fil.cc:2753
#11 0x0000000000ad5df0 in row_drop_table_for_mysql (name=0x7fd828641901 "\260", <incomplete sequence \340>, trx=<optimized out>, drop_db=<optimized out>, nonatomic=<optimized out>) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/innobase/row/row0mysql.cc:4242
#12 0x0000000000a0780f in ha_innobase::delete_table (this=<optimized out>, name=0x7fd828642dc0 "./test/trigger120626") at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/innobase/handler/ha_innodb.cc:10460
#13 0x00000000005c0e66 in ha_delete_table (thd=0x2656660, table_type=<optimized out>, path=0x7fd828642dc0 "./test/trigger120626", db=0x7fd7b0005410 "test", alias=0x7fd7b0004e68 "trigger120626", generate_warning=true) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/handler.cc:2367
#14 0x000000000077e5de in mysql_rm_table_no_locks (thd=0x2656660, tables=0x7fd7b0004eb0, if_exists=true, drop_temporary=false, drop_view=false, dont_log_query=false) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/sql_table.cc:2467
#15 0x000000000077f6f6 in mysql_rm_table (thd=0x2656660, tables=0x7fd7b0004eb0, if_exists=1 '\001', drop_temporary=0 '\000') at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/sql_table.cc:2163
#16 0x0000000000724cb2 in mysql_execute_command (thd=0x2656660) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/sql_parse.cc:3931
#17 0x0000000000729108 in mysql_parse (thd=0x2656660, rawbuf=0x2658a50 "P#9\001", length=<optimized out>, parser_state=<optimized out>) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/sql_parse.cc:6569
#18 0x000000000072a26c in dispatch_command (command=COM_QUERY, thd=0x2656660, packet=0x7fd828644910 "`fe\002", packet_length=61) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/sql_parse.cc:1436
#19 0x000000000072b467 in do_command (thd=0x2656660) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/sql_parse.cc:1051
#20 0x00000000007d8b4f in threadpool_process_request (thd=0x2656660) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/threadpool_common.cc:313
#21 0x00000000007db898 in handle_event (connection=0x2583990) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/threadpool_unix.cc:1466
#22 worker_main (param=0x1523a00 <all_groups+2048>) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/sql/threadpool_unix.cc:1519
#23 0x00000000009e199a in pfs_spawn_thread (arg=0x7fd7c4037200) at /bzr/5.6-QA_dbg/Percona-Server-5.6.13-rc60.5/storage/perfschema/pfs.cc:1858
#24 0x0000003637207851 in start_thread () from /lib64/libpthread.so.0
#25 0x0000003636ee890d in clone () from /lib64/libc.so.6