Prepared statements with fields longtext and longblob cause segmentation fault

[iMega]

Problem: prepared statements with fields longtext and longblob cause segmentation fault if fields value is not equal NULL.

mysql dump

CREATE TABLE `mytable` (
  `pri` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `f_longtext` longtext NOT NULL,
  `f_longtext_null` longtext DEFAULT NULL,
  `f_longblob` longblob NOT NULL,
  `f_longblob_null` longblob DEFAULT NULL,
  PRIMARY KEY (`pri`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `mytable` (`pri`, `f_longtext`, `f_longtext_null`, `f_longblob`, `f_longblob_null`)
VALUES
	(1, '', NULL, '', NULL),
	(2, 'qwe', 'qwe', 'qwe', 'qwe');

tmlapp        | Segmentation fault
tmlapp        |   code: SEGV_MAPERR
tmlapp        |   addr: 0
tmlapp        |   context: 0x7f8cb387f6c0
tmlapp        |   siginfo: 0x7f8cb387f7f0
tmlapp        |   rax      0x0                0
tmlapp        |   rbx      0x5601c2a2c2f8     94565560402680
tmlapp        |   rcx      0x0                0
tmlapp        |   rdx      0x3                3
tmlapp        |   rsi      0x5601c2a07063     94565560250467
tmlapp        |   rdi      0x0                0
tmlapp        |   rsp      0x7f8cb387fd78     140242284182904
tmlapp        |   rbp      0x3                3
tmlapp        |   r8       0x1                1
tmlapp        |   r9       0x0                0
tmlapp        |   r10      0x40dcb718         1088206616
tmlapp        |   r11      0x9                9
tmlapp        |   r12      0x3                3
tmlapp        |   r13      0x5601c2a2a600     94565560395264
tmlapp        |   r14      0x0                0
tmlapp        |   r15      0x5601c2a07061     94565560250465
tmlapp        |   rip      0x7f8d1ba4b0a0     140244030894240
tmlapp        |   eflags   0x10206            66054
tmlapp        |   cs       0x33               51
tmlapp        |   gs       0x0                0
tmlapp        |   fs       0x0                0
tmlapp        |   cr2      0x0                0
tmlapp        |   err      0x6                6
tmlapp        |   oldmask  0x0                0
tmlapp        |   trapno   0xe                14
tmlapp        | Current time: 1574495001
tmlapp        | Please file a bug at http://github.com/tarantool/tarantool/issues
tmlapp        | Attempting backtrace... Note: since the server has already crashed,
tmlapp        | this may fail as well
tmlapp        | #0  0x5601c1c7d219 in print_backtrace+9
tmlapp        | #1  0x5601c1b68dda in _ZL12sig_fatal_cbiP9siginfo_tPv+ca
tmlapp        | #2  0x7f8d1ba40e17 in sigwaitinfo+8

Reproduce case:

tarantool> mysql = require("mysql")
---
...
tarantool> pool = mysql.pool_create({host = 'localhost', db = 'test', size = 5})
---
...
tarantool> conn = pool:get()
---
...
tarantool> conn:execute("select `f_longtext` from mytable where pri = ?", 1)
---
- error: null  <-- crash
...
tarantool> conn:execute("select `f_longblob` from mytable where pri = ?", 1)
---
- error: null  <-- crash
...
tarantool> conn:execute("select `f_longtext_null` from mytable where pri = ?", 2)
---
- error: null  <-- crash
...
tarantool> conn:execute("select `f_longblob_null` from mytable where pri = ?", 2)
---
- error: null  <-- crash
...

working cases

tarantool> conn:execute("select `f_longtext` from mytable where pri = 1") <-- without prepare
tarantool> conn:execute("select `f_longtext_null` from mytable where pri = ?", 1) <-- if NULL
tarantool> conn:execute("select `f_longblob_null` from mytable where pri = ?", 1) <-- if NULL

my working example with mariadb-connector-c https://github.com/iMega/tarantool-mysql-learning/blob/master/mysqltest/main.c

app crashes here https://github.com/tarantool/mariadb-connector-c/blob/c5dfd891257f4dca3d1f6aa7645d27f6b491c6a6/libmariadb/mariadb_stmt.c#L1253

[better0fdead]

Couldn't reproduce. Tested on Ubuntu 20.4.
Used tarantool:

• 1.10.5
• 1.10.10
• 2.10.0
• 2.10.3

Used mysql-server:

• 8.0.30
• 5.7.39

@iMega It would be nice if you can check again that bug on ur side or/and provide versions.