Thread 1 (Thread 0x7f1e8904e740 (LWP 6393)):

#0  __lll_lock_wait_private ()

    at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95

#1  0x00007f1e87f8371b in __run_exit_handlers (status=5, 

    listp=0x7f1e88300718 <__exit_funcs>, 

    run_list_atexit=run_list_atexit@entry=true, run_dtors=run_dtors@entry=true)

    at exit.c:56

#2  0x00007f1e87f8392a in __GI_exit (status=<optimized out>) at exit.c:139

#3  0x0000558b27bce288 in kill_child (was_killed=false)

    at /mariadb/10.3/mysql-test/lib/My/SafeProcess/safe_process.cc:119

#4  0x0000558b27bce32e in handle_signal (sig=15)

    at /mariadb/10.3/mysql-test/lib/My/SafeProcess/safe_process.cc:139

#5  <signal handler called>

#6  __run_exit_handlers (status=0, listp=0x7f1e88300718 <__exit_funcs>, 

    run_list_atexit=run_list_atexit@entry=true, run_dtors=run_dtors@entry=true)

    at exit.c:120

#7  0x00007f1e87f8392a in __GI_exit (status=<optimized out>) at exit.c:139

#8  0x0000558b27bce249 in kill_child (was_killed=true)

    at /mariadb/10.3/mysql-test/lib/My/SafeProcess/safe_process.cc:111

#9  0x0000558b27bce32e in handle_signal (sig=17)

    at /mariadb/10.3/mysql-test/lib/My/SafeProcess/safe_process.cc:139

#10 <signal handler called>

#11 0x00007f1e88010404 in __GI___nanosleep (

    requested_time=requested_time@entry=0x7ffe7a09e860, 

    remaining=remaining@entry=0x7ffe7a09e860)

    at ../sysdeps/unix/sysv/linux/nanosleep.c:28

#12 0x00007f1e8801030a in __sleep (seconds=0) at ../sysdeps/posix/sleep.c:55

#13 0x0000558b27bce9cf in main (argc=10, argv=0x7ffe7a09eb08)

    at /mariadb/10.3/mysql-test/lib/My/SafeProcess/safe_process.cc:301