[MDEV-32324] Server crashes inside filesort at my_decimal::to_binary Created: 2023-09-30  Updated: 2023-12-15  Resolved: 2023-10-16

Status: Closed
Project: MariaDB Server
Component/s: Optimizer
Affects Version/s: 10.4, 10.5, 10.6, 10.9, 10.10, 10.11, 11.0, 11.1.2, 11.2.1
Fix Version/s: 10.4.32, 10.5.23, 10.6.16, 10.10.7, 10.11.6, 11.0.4, 11.1.3, 11.2.2, 11.3.1

Type: Bug Priority: Major
Reporter: Jingzhou Fu Assignee: Sergei Petrunia
Resolution: Fixed Votes: 0
Labels: None
Environment:

Ubuntu 20.04 x86-64, docker image mariadb:11.1.2

Issue Links:
Duplicate
is duplicated by MDEV-32606 Server crash when querying InnoDB table Closed
Relates
relates to MDEV-25994 Crash with union of my_decimal type i... Closed

 Description   

PoC:

SELECT 1.000000 two UNION SELECT 1 ORDER BY ( SELECT two LIMIT 1 OFFSET 1 ) ;

docker log:

mariadbd(my_print_stacktrace+0x32)[0x55edbccc87c2]
 
mariadbd(handle_fatal_signal+0x488)[0x55edbc7a1cf8]
 
/lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7f2de8831520]
 
mariadbd(_ZNK10my_decimal9to_binaryEPhitj+0x31)[0x55edbc8ed5c1]
 
mariadbd(_ZNK27Type_handler_decimal_result18make_sort_key_partEPhP4ItemPK15SORT_FIELD_ATTRP6String+0x6d)[0x55edbc79ccdd]
 
mariadbd(+0xaa1dc2)[0x55edbc79ddc2]
 
mariadbd(_Z8filesortP3THDP5TABLEP8FilesortP16Filesort_trackerP4JOINy+0x15d7)[0x55edbc7a06c7]
 
mariadbd(_Z17create_sort_indexP3THDP4JOINP13st_join_tableP8Filesort+0xea)[0x55edbc595dfa]
 
mariadbd(_ZN13st_join_table10sort_tableEv+0x8b)[0x55edbc59618b]
 
mariadbd(_Z21join_init_read_recordP13st_join_table+0x71)[0x55edbc596251]
 
mariadbd(_Z10sub_selectP4JOINP13st_join_tableb+0x22f)[0x55edbc57c9ff]
 
mariadbd(_ZN4JOIN10exec_innerEv+0xfd4)[0x55edbc5b0bc4]
 
mariadbd(_ZN4JOIN4execEv+0x3f)[0x55edbc5b0fff]
 
mariadbd(_Z12mysql_selectP3THDP10TABLE_LISTR4ListI4ItemEPS4_jP8st_orderS9_S7_S9_yP13select_resultP18st_select_lex_unitP13st_select_lex+0x12c)[0x55edbc5aef7c]
 
mariadbd(_ZN18st_select_lex_unit10exec_innerEv+0x68c)[0x55edbc60341c]
 
mariadbd(_Z11mysql_unionP3THDP3LEXP13select_resultP18st_select_lex_unity+0x48)[0x55edbc606438]
 
mariadbd(_Z13handle_selectP3THDP3LEXP13select_resulty+0x59)[0x55edbc5af679]
 
mariadbd(+0x826f55)[0x55edbc522f55]
 
mariadbd(_Z21mysql_execute_commandP3THDb+0x419e)[0x55edbc531f0e]
 
mariadbd(_Z11mysql_parseP3THDPcjP12Parser_state+0x1e7)[0x55edbc533237]
 
mariadbd(_Z16dispatch_command19enum_server_commandP3THDPcjb+0x14bd)[0x55edbc535a1d]
 
mariadbd(_Z10do_commandP3THDb+0x138)[0x55edbc537818]
 
mariadbd(_Z24do_handle_one_connectionP7CONNECTb+0x3bf)[0x55edbc65f3af]
 
mariadbd(handle_one_connection+0x5d)[0x55edbc65f6fd]
 
mariadbd(+0xcd1906)[0x55edbc9cd906]
 
/lib/x86_64-linux-gnu/libc.so.6(+0x94b43)[0x7f2de8883b43]
 
/lib/x86_64-linux-gnu/libc.so.6(clone+0x44)[0x7f2de8914bb4]
 
 
 
Trying to get some variables.
 
Some pointers may be invalid and cause the dump to abort.
 
Query (0x7f2d840130d8): SELECT 1.000000 two UNION SELECT 1 ORDER BY ( SELECT two LIMIT 1 OFFSET 1 )
 
 
 
Connection ID (thread ID): 4
 
Status: NOT_KILLED
 
 
 
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,hash_join_cardinality=on



 Comments   
Comment by Alice Sherepa [ 2023-10-03 ]

Thank you for the report!
I repeated as described on 10.4-11.2

Version: '10.4.32-MariaDB-debug-log' 
231003 15:27:14 [ERROR] mysqld got signal 11 ;
 
 
 
Server version: 10.4.32-MariaDB-debug-log source revision: 50a2e8b1892b6b8a276d4bd75a1a02148f9e6ff2
 
 
 
sql/signal_handler.cc:238(handle_fatal_signal)[0x55f3cb51d7e9]
 
sigaction.c:0(__restore_rt)[0x7fdb1ba02420]
 
sql/my_decimal.h:128(my_decimal::operator=(my_decimal const&))[0x55f3cb2fcc8d]
 
sql/my_decimal.h:332(my_decimal2decimal(my_decimal const*, my_decimal*))[0x55f3cb2fd059]
 
sql/my_decimal.cc:206(my_decimal::to_binary(unsigned char*, int, int, unsigned int) const)[0x55f3cb8db506]
 
sql/filesort.cc:1159(Type_handler_decimal_result::make_sort_key(unsigned char*, Item*, SORT_FIELD_ATTR const*, String*) const)[0x55f3cb513c9b]
 
sql/filesort.cc:1207(make_sortkey(Sort_param*, unsigned char*, unsigned char*))[0x55f3cb514168]
 
sql/filesort.cc:849(find_all_keys(THD*, Sort_param*, SQL_SELECT*, SORT_INFO*, st_io_cache*, st_io_cache*, Bounded_queue<unsigned char, unsigned char>*, unsigned long long*))[0x55f3cb511496]
 
sql/filesort.cc:262(filesort(THD*, TABLE*, Filesort*, Filesort_tracker*, JOIN*, unsigned long long))[0x55f3cb50cd8d]
 
sql/sql_select.cc:24212(create_sort_index(THD*, JOIN*, st_join_table*, Filesort*))[0x55f3caec37dc]
 
sql/sql_select.cc:21890(st_join_table::sort_table())[0x55f3caeb1f3d]
 
sql/sql_select.cc:21829(join_init_read_record(st_join_table*))[0x55f3caeb143f]
 
sql/sql_select.cc:20899(sub_select(JOIN*, st_join_table*, bool))[0x55f3caeaab58]
 
sql/sql_select.cc:20423(do_select(JOIN*, Procedure*))[0x55f3caea8aba]
 
sql/sql_select.cc:4605(JOIN::exec_inner())[0x55f3cae36602]
 
sql/sql_select.cc:4388(JOIN::exec())[0x55f3cae33c2e]
 
sql/sql_select.cc:4828(mysql_select(THD*, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*))[0x55f3cae37e0e]
 
sql/sql_union.cc:1729(st_select_lex_unit::exec())[0x55f3cb02de2a]
 
sql/sql_union.cc:42(mysql_union(THD*, LEX*, select_result*, st_select_lex_unit*, unsigned long))[0x55f3cb01bcb2]
 
sql/sql_select.cc:432(handle_select(THD*, LEX*, select_result*, unsigned long))[0x55f3cae085eb]
 
sql/sql_parse.cc:6475(execute_sqlcom_select(THD*, TABLE_LIST*))[0x55f3cad7472c]
 
sql/sql_parse.cc:3978(mysql_execute_command(THD*))[0x55f3cad61ea3]
 
sql/sql_parse.cc:8012(mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool))[0x55f3cad7dc07]
 
sql/sql_parse.cc:1860(dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool))[0x55f3cad5402d]
 
sql/sql_parse.cc:1378(do_command(THD*))[0x55f3cad50b58]
 
sql/sql_connect.cc:1420(do_handle_one_connection(CONNECT*))[0x55f3cb15e7fd]
 
sql/sql_connect.cc:1325(handle_one_connection)[0x55f3cb15e0a1]
 
perfschema/pfs.cc:1871(pfs_spawn_thread)[0x55f3cbe0899a]
 
nptl/pthread_create.c:478(start_thread)[0x7fdb1b9f6609]
 
/lib/x86_64-linux-gnu/libc.so.6(clone+0x43)[0x7fdb1b5c7133]
 
 
 
Query (0x62b0000a1420): SELECT 1.000000 two UNION SELECT 1 ORDER BY ( SELECT two LIMIT 1 OFFSET 1 )

Comment by Sergei Petrunia [ 2023-10-12 ]

The subquery ( SELECT two LIMIT 1 OFFSET 1 ) returns an empty set. But it has maybe_null=false. This confuses the sorting code.

Comment by Sergei Petrunia [ 2023-10-12 ]

A related fix

commit 3c209bfc040ddfc41ece8357d772547432353fd2
 
Author:	Sergei Petrunia <sergey@mariadb.com>  Thu Apr 21 15:03:23 2022
 
Committer:	Sergei Petrunia <sergey@mariadb.com>  Fri Apr 22 13:57:16 2022
 
 
 
MDEV-25994: Crash with union of my_decimal type in ORDER BY clause
 
 
 
    When single-row subquery fails with "Subquery reutrns more than 1 row"
 
    error, it will raise an error and return NULL.
 
    
    On the other hand, Item_singlerow_subselect sets item->maybe_null=0
 
    for table-less subqueries like "(SELECT not_null_value)"  (*)
 
    
    This discrepancy (item with maybe_null=0 returning NULL) causes the
 
    code in Type_handler_decimal_result::make_sort_key_part() to crash.
 
    
    Fixed this by allowing inference (*) only when the subquery is NOT a
 
    UNION.

Comment by Sergei Petrunia [ 2023-10-12 ]

bb-10.4-MDEV-32324

Comment by Sergei Petrunia [ 2023-10-12 ]

Oleg, please review.

Comment by Oleg Smirnov [ 2023-10-16 ]

A couple of cosmetic comments are left at GitHub, otherwise legitimate.

Comment by Sergei Petrunia [ 2023-10-16 ]

Addressed comments on github.

Generated at Thu Feb 08 10:30:29 UTC 2024 using Jira 8.20.16#820016-sha1:9d11dbea5f4be3d4cc21f03a88dd11d8c8687422.