.
Thread 4 (LWP 1992):
#0  0x00007f7ee55c13cd in ?? ()
No symbol table info available.
#1  0x0000000000000000 in ?? ()
No symbol table info available.
.
Thread 3 (LWP 1985):
#0  0x00007f7ee55c13cd in ?? ()
No symbol table info available.
#1  0x0000000000000000 in ?? ()
No symbol table info available.
.
Thread 2 (LWP 1989):
#0  0x00007f7ee55c13cd in ?? ()
No symbol table info available.
#1  0x0000000000000000 in ?? ()
No symbol table info available.
.
Thread 1 (LWP 1978):
#0  0x00007f7ee550b037 in ?? ()
No symbol table info available.
#1  0x00007f7ee550e698 in ?? ()
No symbol table info available.
#2  0x0000000000000020 in ?? ()
No symbol table info available.
#3  0x0000000000000000 in ?? ()
No symbol table info available.