[MDEV-26357] Crash in Item_param::convert_str_value Created: 2021-08-13  Updated: 2021-08-13  Resolved: 2021-08-13

Status: Closed
Project: MariaDB Server
Component/s: N/A
Affects Version/s: 10.5.12
Fix Version/s: N/A

Type: Bug Priority: Major
Reporter: markus makela Assignee: Unassigned
Resolution: Duplicate Votes: 0
Labels: None

Issue Links:
Duplicate
duplicates MDEV-19811 Crash with prepared statement Open

 Description   

Was testing MaxScale version 6 with 10.5.12 and observed the following crash in both 10.5.12 and 10.5.12

210813  9:03:30 [ERROR] mysqld got signal 11 ;
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: 10.5.12-MariaDB-1:10.5.12+maria~focal-log
key_buffer_size=134217728
read_buffer_size=131072
max_used_connections=11
max_threads=153
thread_count=14
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 467871 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.
Thread pointer: 0x7f29e8000c58
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 = 0x7f2a41491d58 thread_stack 0x49000
mysqld(my_print_stacktrace+0x32)[0x55b96c8b73a2]
Printing to addr2line failed
mysqld(handle_fatal_signal+0x485)[0x55b96c30a0b5]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x153c0)[0x7f2a595623c0]
mysqld(my_string_metadata_get+0x1e)[0x55b96c90721e]
mysqld(_ZN10Item_param17convert_str_valueEP3THD+0xdf)[0x55b96c32f26f]
mysqld(+0x779347)[0x55b96c10b347]
mysqld(_ZN18Prepared_statement14set_parametersEP6StringPhS2_+0x6f)[0x55b96c10f96f]
mysqld(_ZN18Prepared_statement12execute_loopEP6StringbPhS2_+0x3a)[0x55b96c110a7a]
mysqld(+0x77f735)[0x55b96c111735]
mysqld(_Z19mysqld_stmt_executeP3THDPcj+0x30)[0x55b96c111950]
mysqld(_Z16dispatch_command19enum_server_commandP3THDPcjbb+0x1acf)[0x55b96c0f847f]
mysqld(_Z10do_commandP3THD+0x11c)[0x55b96c0fa30c]
mysqld(_Z24do_handle_one_connectionP7CONNECTb+0x421)[0x55b96c200a61]
mysqld(handle_one_connection+0x5d)[0x55b96c200edd]
mysqld(+0xbd0a36)[0x55b96c562a36]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x9609)[0x7f2a59556609]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x43)[0x7f2a59144293]
Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (0x0): (null)
Connection ID (thread ID): 11
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
The manual page at https://mariadb.com/kb/en/how-to-produce-a-full-stack-trace-for-mysqld/ contains
information that should help you find out what is causing the crash.
We think the query pointer is invalid, but we will try to print it anyway. 
Query: 
Writing a core file...
Working directory at /var/lib/mysql
Resource Limits:
Limit                     Soft Limit           Hard Limit           Units     
Max cpu time              unlimited            unlimited            seconds   
Max file size             unlimited            unlimited            bytes     
Max data size             unlimited            unlimited            bytes     
Max stack size            8388608              unlimited            bytes     
Max core file size        unlimited            unlimited            bytes     
Max resident set          unlimited            unlimited            bytes     
Max processes             unlimited            unlimited            processes 
Max open files            1024                 1024                 files     
Max locked memory         65536                65536                bytes     
Max address space         unlimited            unlimited            bytes     
Max file locks            unlimited            unlimited            locks     
Max pending signals       127158               127158               signals   
Max msgqueue size         819200               819200               bytes     
Max nice priority         0                    0                    
Max realtime priority     0                    0                    
Max realtime timeout      unlimited            unlimited            us        
Core pattern: |/usr/lib/systemd/systemd-coredump %P %u %g %s %t %c %h

The sysbench command I ran:

sysbench --time=0 --threads=5 --mysql-host=127.0.0.1 --mysql-port=4006 --mysql-user=maxuser --mysql-password=maxpwd --mysql-db=test --db-ps-mode=auto --skip_trx=on ./oltp_read_only.lua run

The MaxScale configuration:

[maxscale]
threads=auto
 
[server1]
type=server
address=127.0.0.1
port=3000
protocol=MariaDBBackend
persistpoolmax=20
persistmaxtime=300s
 
[server2]
type=server
address=127.0.0.1
port=3001
protocol=MariaDBBackend
persistpoolmax=20
persistmaxtime=300s
 
[server3]
type=server
address=127.0.0.1
port=3002
protocol=MariaDBBackend
persistpoolmax=20
persistmaxtime=300s
 
[server4]
type=server
address=127.0.0.1
port=3003
protocol=MariaDBBackend
persistpoolmax=20
persistmaxtime=300s
 
[MariaDB-Monitor]
type=monitor
module=mariadbmon
servers=server1,server2,server3,server4
user=maxuser
password=maxpwd
monitor_interval=5000
 
[RW-Split-Router]
type=service
router=readwritesplit
servers=server1,server2,server3,server4
user=maxuser
password=maxpwd
idle_session_pool_time=0s
 
[RW-Split-Listener]
type=listener
service=RW-Split-Router
protocol=MariaDBClient
port=4006

I was using a modified version of MaxScale with the following patch applied to commit d9f14315a0ba075c61d7fe9fa4e403534517787c:

diff --git a/server/core/routingworker.cc b/server/core/routingworker.cc
index 0d08600e4..23a6e78b3 100644
--- a/server/core/routingworker.cc
+++ b/server/core/routingworker.cc
@@ -465,7 +465,7 @@ void RoutingWorker::process_timeouts()
                 auto idle = MXS_CLOCK_TO_SEC(now - pClient->last_read());
                 pSes->tick(idle);
 
-                if (pooling_time >= 0 && idle > pooling_time && pSes->can_pool_backends())
+                if (pooling_time >= 0 && idle >= pooling_time && pSes->can_pool_backends())
                 {
                     for (auto& backend : pSes->backend_connections())
                     {



 Comments   
Comment by markus makela [ 2021-08-13 ]

I guess I ran into this before: MDEV-19811

Comment by markus makela [ 2021-08-13 ]

Closing as a duplicate of MDEV-19811.

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