Description:
MySQL 8.0.42-debug crashes with a critical assertion failure (Assertion '!unsigned_flag || !arg_val.is_negative()' failed) when executing queries involving LEAST() with unsigned columns and negative values. This is a severe stability bug causing complete server crashes.
How to repeat:
DROP DATABASE IF EXISTS database12;
CREATE DATABASE database12;
USE database12;
SET GLOBAL host_cache_size = 65536;
SET GLOBAL tmp_table_size = 1024;
CREATE TABLE `t2` (
`c0` tinyint(107) unsigned zerofill DEFAULT NULL,
UNIQUE KEY `i0` (`c0` DESC)
);
SELECT t2.c0 AS ref0 FROM t2 WHERE (NOT ((+ (((t2.c0) NOT IN (-952979894)) OR (LEAST(t2.c0, t2.c0))))));
No connection. Trying to reconnect...
Connection id: 8
Current database: database12
ERROR 2013 (HY000): Lost connection to MySQL server during query
No connection. Trying to reconnect...
When executing the query statement, the database crashed.
mysqld: /home/tzx/mysql-server-mysql-8.0.42/sql/item_func.cc:3937: virtual longlong Item_func_min_max::int_op(): Assertion `!unsigned_flag || !arg_val.is_negative()' failed.
2026-01-07T08:58:33Z UTC - mysqld got signal 6 ;
Most likely, you have hit a bug, but this error can also be caused by malfunctioning hardware.
BuildID[sha1]=74c66055f3de3ce92689b61f26f34703359b2316
Thread pointer: 0x7f9f64001050
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...
stack_bottom = 7fa0144f39b8 thread_stack 0x100000
/usr/local/mysql/bin/mysqld(my_print_stacktrace(unsigned char const*, unsigned long)+0x4c) [0x55e516b93edc]
/usr/local/mysql/bin/mysqld(print_fatal_signal(int)+0x398) [0x55e514a9d2e8]
/usr/local/mysql/bin/mysqld(handle_fatal_signal+0x69) [0x55e514a9d4c9]
/lib/x86_64-linux-gnu/libc.so.6(+0x42520) [0x7fa02bacf520]
/lib/x86_64-linux-gnu/libc.so.6(pthread_kill+0x12c) [0x7fa02bb239fc]
/lib/x86_64-linux-gnu/libc.so.6(raise+0x16) [0x7fa02bacf476]
/lib/x86_64-linux-gnu/libc.so.6(abort+0xd3) [0x7fa02bab57f3]
/lib/x86_64-linux-gnu/libc.so.6(+0x2871b) [0x7fa02bab571b]
/lib/x86_64-linux-gnu/libc.so.6(+0x39e96) [0x7fa02bac6e96]
/usr/local/mysql/bin/mysqld(Item_func_min_max::int_op()+0x584) [0x55e514e5cbc4]
/usr/local/mysql/bin/mysqld(Arg_comparator::compare_int_signed_unsigned()+0x121) [0x55e514da6371]
/usr/local/mysql/bin/mysqld(Item_func_eq::val_int()+0x85) [0x55e514dac1e5]
/usr/local/mysql/bin/mysqld(Item::val_bool()+0x86) [0x55e514d4a6a6]
/usr/local/mysql/bin/mysqld(eval_const_cond(THD*, Item*, bool*)+0x6e) [0x55e514e3ab2e]
/usr/local/mysql/bin/mysqld(remove_eq_conds(THD*, Item*, Item**, Item::cond_result*)+0x77d) [0x55e51472172d]
/usr/local/mysql/bin/mysqld(remove_eq_conds(THD*, Item*, Item**, Item::cond_result*)+0x254) [0x55e514721204]
/usr/local/mysql/bin/mysqld(optimize_cond(THD*, Item**, COND_EQUAL**, mem_root_deque<Table_ref*>*, Item::cond_result*)+0xb33) [0x55e514712553]
/usr/local/mysql/bin/mysqld(JOIN::optimize(bool)+0x1934) [0x55e51470dfd4]
/usr/local/mysql/bin/mysqld(Query_block::optimize(THD*, bool)+0x1cf) [0x55e51483d31f]
/usr/local/mysql/bin/mysqld(Query_expression::optimize(THD*, TABLE*, bool, bool)+0x162) [0x55e51493f5e2]
/usr/local/mysql/bin/mysqld(Sql_cmd_dml::execute_inner(THD*)+0x4c) [0x55e51483805c]
/usr/local/mysql/bin/mysqld(Sql_cmd_dml::execute(THD*)+0x99d) [0x55e51483699d]
/usr/local/mysql/bin/mysqld(mysql_execute_command(THD*, bool)+0x4e93) [0x55e5147678a3]
/usr/local/mysql/bin/mysqld(dispatch_sql_command(THD*, Parser_state*)+0xfa8) [0x55e51475f0d8]
/usr/local/mysql/bin/mysqld(dispatch_command(THD*, COM_DATA const*, enum_server_command)+0x4792) [0x55e514759d32]
/usr/local/mysql/bin/mysqld(do_command(THD*)+0x9de) [0x55e51475ca8e]
/usr/local/mysql/bin/mysqld(+0x170b554) [0x55e514a78554]
/usr/local/mysql/bin/mysqld(+0x48e64dc) [0x55e517c534dc]
/lib/x86_64-linux-gnu/libc.so.6(+0x94ac3) [0x7fa02bb21ac3]
