main.connect_debug failed in buildbot with server crash in unlink_thd / threadpool_remove_connection

main.connect_debug                       w2 [ fail ]

        Test ended at 2020-06-11 18:52:26

CURRENT_TEST: main.connect_debug

ERROR 1043 (08S01): Bad handshake

mysqltest: At line 39: query 'set global debug_dbug=@old_dbug' failed: 2013: Lost connection to MySQL server during query

The result from queries just before the failure was:

< snip >

drop user bad;

set global debug_dbug='+d,auth_invalid_plugin';

create user 'bad' identified by 'worse';

ERROR 1045 (28000): Plugin foo/bar could not be loaded: invalid plugin name

set global debug_dbug=@old_dbug;

drop user bad;

set global debug_dbug='+d,increase_srv_handshake_scramble_len';

connect(localhost,root,,test,MASTER_MYPORT,MYSQL_TMP_DIR/mysqld.1.sock);

connect con1,localhost,root;

ERROR HY000: received malformed packet

set global debug_dbug=@old_dbug;

set global debug_dbug='+d,poison_srv_handshake_scramble_len';

connect(localhost,root,,test,MASTER_MYPORT,MYSQL_TMP_DIR/mysqld.1.sock);

connect con2,localhost,root;

ERROR HY000: received malformed packet

set global debug_dbug=@old_dbug;

More results from queries before failure can be found in D:\win32-debug\build\mysql-test\var\2\log\connect_debug.log

Server [mysqld.1 - pid: 37452, winpid: 37452, exit: 1280] failed during test run

Server log from this test:

----------SERVER LOG START-----------

2020-06-11 18:52:24 312 [Warning] Access denied for user 'bad'@'localhost' (using password: NO)

2020-06-11 18:52:24 313 [Warning] Aborted connection 313 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (Got an error reading communication packets)

2020-06-11 18:52:24 313 [Warning] Aborted connection 313 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)

2020-06-11 18:52:24 314 [Warning] Aborted connection 314 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (Got an error reading communication packets)

2020-06-11 18:52:24 314 [Warning] Aborted connection 314 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)

200611 18:52:24 [ERROR] mysqld got exception 0xc0000005 ;

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.

To report this bug, see https://mariadb.com/kb/en/reporting-bugs

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.

Server version: 10.5.4-MariaDB-debug-log

key_buffer_size=1048576

read_buffer_size=131072

max_used_connections=3

max_threads=65537

thread_count=3

It is possible that mysqld could use up to 

key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 3676 K  bytes of memory

Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x56b1ff0

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...

server.dll!_db_doprnt_()[dbug.c:1314]

server.dll!unlink_thd()[mysqld.cc:2597]

server.dll!threadpool_remove_connection()[threadpool_common.cc:287]

server.dll!threadpool_add_connection()[threadpool_common.cc:276]

server.dll!tp_callback()[threadpool_common.cc:186]

server.dll!TP_pool_win::add()[threadpool_win.cc:120]

server.dll!tp_add_connection()[threadpool_common.cc:408]

server.dll!create_new_thread()[mysqld.cc:6010]

server.dll!handle_accepted_socket()[mysqld.cc:6075]

server.dll!Socket_Listener::completion_callback()[handle_connections_win.cc:269]

server.dll!Socket_Listener::tp_accept_completion_callback()[handle_connections_win.cc:155]

KERNEL32.DLL!SetUserGeoName()

ntdll.dll!RtlAcquireResourceExclusive()

ntdll.dll!RtlAcquirePebLock()

KERNEL32.DLL!BaseThreadInitThunk()

ntdll.dll!RtlGetAppContainerNamedObjectPath()

ntdll.dll!RtlGetAppContainerNamedObjectPath()

Trying to get some variables.

Some pointers may be invalid and cause the dump to abort.

Query (0x0): 

Connection ID (thread ID): 314

Status: KILL_CONNECTION

Optimizer switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off

The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains

information that should help you find out what is causing the crash.

Writing a core file at D:\win32-debug\build\mysql-test\var\2\mysqld.1\data\

Minidump written to D:\win32-debug\build\mysql-test\var\2\mysqld.1\data\mariadbd.dmp

----------SERVER LOG END-------------