[ERROR] ProxySQL crashed. Restarting!

[dmstahl]

I am running ProxySQL version 1.4.9-3-gd9fd599 on Ubuntu 16.04.1 and received the following error:

Error: signal 11:
proxysql(_Z13crash_handleri+0x2d)[0x449e4d]
/lib/x86_64-linux-gnu/libc.so.6(+0x354b0)[0x7fe2ffdc64b0]
proxysql(net_field_length+0x3)[0x62db73]
proxysql(mthd_stmt_read_all_rows+0x163)[0x638973]
proxysql(mysql_stmt_store_result+0x8a)[0x63a89a]
proxysql[0x634b38]
proxysql(my_context_spawn+0x41)[0x633b11]
2018-08-08 10:52:32 main.cpp:905:ProxySQL_daemonize_phase3(): [ERROR] ProxySQL crashed. Restarting!

[renecannao]

Do you have a core dump?

[dmstahl]

Hi @renecannao, I sent you a link to the core dump. Thanks!

[dmstahl]

The query that we are running when we receive the crash is returning some JSON data from the database. The crash appears to happen when the JSON data is 254-255 bytes (or is 509-510 bytes -> a multiple of 255 or one byte less than a multiple of 255) AND contains a null character.

[c4l3b]

Attached is a test to make ProxySQL crash with this error.

• Run the CreateTestTable.sql to create the table and data.
• Adjust the connection variables at the top of test.php.
• Run the test.php using PHP (tested with 7.1 here).

After further testing, the crash might have more to do with the entire length of the row rather than just the length of the JSON.

Proxysql-JSON-crash.zip

[altmannmarcelo]

The error doesn't happen if bellow attribute is set:

        PDO::ATTR_EMULATE_PREPARES => TRUE,

@renecannao - This may be related to https://github.com/MariaDB/mariadb-connector-c/pull/38/files ?

When querying mysql directly it's getting 2036 error:

[root@marcelo-altmann-240074-proxysql-1 ~]# php a.php
Error: exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 2036 ' in /root/a.php:20
Stack trace:
#0 /root/a.php(20): PDO->query('SELECT * FROM t...')
#1 {main}

mysql->read_pos is null:

(gdb) p pos
$8 = (uchar *) 0x17d0c3c000 <Address 0x17d0c3c000 out of bounds>
(gdb) p *mysql
$9 = {net = {vio = 0x7ff0d0024280, buff = 0x7ff0d00ed000 "\n", buff_end = 0x7ff0d00ef000 "", write_pos = 0x7ff0d00ed000 "\n",
    read_pos = 0x7ff0d00ed000 "\n", fd = 28, remain_in_buf = 0, length = 0, buf_length = 0, where_b = 0, max_packet = 8192,
    max_packet_size = 1073741824, pkt_nr = 1, compress_pkt_nr = 0, write_timeout = 0, read_timeout = 30, retry_count = 0,
    fcntl = 0, return_status = 0x0, reading_or_writing = 0 '\000', save_char = 0 '\000', unused_1 = 0 '\000', unused_2 = 0 '\000',
    compress = 0 '\000', unused_3 = 0 '\000', unused_4 = 0x0, last_errno = 0, error = 0 '\000', unused_5 = 0 '\000',
    unused_6 = 0 '\000', last_error = '\000' <repeats 511 times>, sqlstate = "00000", extension = 0x0}, unused_0 = 0x0,
  host = 0x7ff0d00174d8 "172.16.2.220", user = 0x7ff0d0023090 "root",
  passwd = 0x7ff0d001cc20 "*a1b9892611956aa13a5ab9ccf01f49662583f2d2", unix_socket = 0x0,
  server_version = 0x7ff0d00181c0 "5.7.23-23-57", host_info = 0x7ff0d00174c0 "172.16.2.220 via TCP/IP", info = 0x0,
  db = 0x7ff0d0023098 "marcelo", charset = 0x9a9ef8 <compiled_charsets+3672>, fields = 0x0, field_alloc = {free = 0x7ff0d00f1000,
    used = 0x0, pre_alloc = 0x0, min_malloc = 32, block_size = 8168, block_num = 5, first_block_usage = 0, error_handler = 0x0},
  affected_rows = 18446744073709551615, insert_id = 0, extra_info = 0, thread_id = 12088, packet_length = 7, port = 3306,
  client_flag = 2073231, server_capabilities = 18446744072669364223, protocol_version = 10, field_count = 9, server_status = 2,
  server_language = 8, warning_count = 0, options = {connect_timeout = 1, read_timeout = 0, write_timeout = 0, port = 0,
    protocol = 0, client_flag = 128, host = 0x0, user = 0x0, password = 0x0, unix_socket = 0x0, db = 0x0, init_command = 0x0,
    my_cnf_file = 0x0, my_cnf_group = 0x0, charset_dir = 0x0, charset_name = 0x7ff0d0023088 "utf8", ssl_key = 0x0, ssl_cert = 0x0,
    ssl_ca = 0x0, ssl_capath = 0x0, ssl_cipher = 0x0, shared_memory_base_name = 0x0, max_allowed_packet = 0, use_ssl = 0 '\000',
    compress = 0 '\000', named_pipe = 0 '\000', unused_1 = 0 '\000', unused_2 = 0 '\000', unused_3 = 0 '\000', unused_4 = 0 '\000',
    methods_to_use = MYSQL_OPT_CONNECT_TIMEOUT, bind_address = 0x0, secure_auth = 0 '\000', report_data_truncation = 0 '\000',
    local_infile_init = 0x0, local_infile_read = 0x0, local_infile_end = 0x0, local_infile_error = 0x0, local_infile_userdata = {
      0x0, 0x0}, extension = 0x7ff0d00e8000}, status = MYSQL_STATUS_READY, free_me = 1 '\001', reconnect = 0 '\000',
  scramble_buff = "mN\024%\024_;%\r*?g\003m*mb>U>", unused_1 = 0 '\000', unused_2 = 0x0, unused_3 = 0x0, unused_4 = 0x0,
  unused_5 = 0x0, stmts = 0x7ff0d0c3c310, methods = 0x9b0680 <MARIADB_DEFAULT_METHODS>, thd = 0x0, unbuffered_fetch_owner = 0x0,
  info_buffer = 0x0, extension = 0x0}

[renecannao]

Fixed