Crash during shutdown

[renecannao]

A clear description of the issue

If audit log is enabled, proxysql may crash during shutdown

ProxySQL version

2.0.13

OS version

Not relevant

The steps to reproduce the issue

Not sure.
From the backtrace, it is probably enough to shutdown proxysql when it is running with --idle-threads

The full ProxySQL error log (default location: /var/lib/proxysql/proxysql.log)

The only relevant part:

2020-07-20 09:52:43 ProxySQL_GloVars.cpp:9:term_handler(): [WARNING] Received TERM signal: shutdown in progress...
2020-07-20 09:52:43 [INFO] Starting shutdown...
Error: signal 11:
/usr/bin/proxysql(_Z13crash_handleri+0x1a)[0x4b8a1a]
/lib64/libc.so.6(+0x36340)[0x7fbf29898340]
/lib64/libpthread.so.0(pthread_mutex_lock+0x0)[0x7fbf2aa79c30]
/usr/bin/proxysql(_ZN12MySQL_Thread3runEv+0x1bfa)[0x5017aa]
/usr/bin/proxysql(_Z30mysql_worker_thread_func_idlesPv+0x6c)[0x4b1b6c]
/lib64/libpthread.so.0(+0x7dd5)[0x7fbf2aa77dd5]
/lib64/libc.so.6(clone+0x6d)[0x7fbf2996002d]
2020-07-20 09:52:43 main.cpp:1581:ProxySQL_daemonize_phase3(): [ERROR] ProxySQL crashed. Restarting!

A backtrace:

(gdb) bt
#0  0x00007fbf2aa79c30 in pthread_mutex_lock () from /lib64/libpthread.so.0
#1  0x00000000005017aa in MySQL_Thread::run (this=this@entry=0x7fbf1fa62400) at MySQL_Thread.cpp:4039
#2  0x00000000004b1b6c in mysql_worker_thread_func_idles (arg=0x7fbf249b70f0) at main.cpp:799
#3  0x00007fbf2aa77dd5 in start_thread () from /lib64/libpthread.so.0
#4  0x00007fbf2996002d in clone () from /lib64/libc.so.6
(gdb) bt full
#0  0x00007fbf2aa79c30 in pthread_mutex_lock () from /lib64/libpthread.so.0
No symbol table info available.
#1  0x00000000005017aa in MySQL_Thread::run (this=this@entry=0x7fbf1fa62400) at MySQL_Thread.cpp:4039
        w = <optimized out>
        thr = 0x0
        num_idles = <optimized out>
        ttw = <optimized out>
        maintenance_interval = <optimized out>
        idle_maintenance_thread = <optimized out>
        __PRETTY_FUNCTION__ = "void MySQL_Thread::run()"
        __func__ = "run"
        n = <optimized out>
        rc = <optimized out>
#2  0x00000000004b1b6c in mysql_worker_thread_func_idles (arg=0x7fbf249b70f0) at main.cpp:799
        thread_attr = {__size = '\000' <repeats 17 times>, "\020", '\000' <repeats 37 times>, __align = 0}
        tmp_stack_size = 8388608
        mysql_thread = 0x7fbf249b70f0
        worker = 0x7fbf1fa62400
#3  0x00007fbf2aa77dd5 in start_thread () from /lib64/libpthread.so.0
No symbol table info available.
#4  0x00007fbf2996002d in clone () from /lib64/libc.so.6
No symbol table info available.