.
Thread 3 (Thread 0x7f6a24c3d700 (LWP 2057)):
#0  0x00007f6a291c8d84 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007f6a285b9a73 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
No symbol table info available.
#2  0x00007f6a291c4e9a in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#3  0x00007f6a2a95777d in clone () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#4  0x0000000000000000 in ?? ()
No symbol table info available.
.
Thread 2 (Thread 0x7f6a2543e700 (LWP 2056)):
#0  0x00007f6a291c8d84 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007f6a285b9a73 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
No symbol table info available.
#2  0x00007f6a291c4e9a in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#3  0x00007f6a2a95777d in clone () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#4  0x0000000000000000 in ?? ()
No symbol table info available.
.
Thread 1 (Thread 0x7f6a2b3be740 (LWP 2053)):
#0  0x00007f6a288e4b60 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
No symbol table info available.
#1  <signal handler called>
No symbol table info available.
#2  0x00007f6a2a950107 in writev () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#3  0x00007f6a2a652945 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
No symbol table info available.
#4  0x00007f6a2a652dbf in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
No symbol table info available.
#5  0x00007f6a2a652e44 in xcb_writev () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
No symbol table info available.
#6  0x00007f6a2aec2a07 in _XSend () from /usr/lib/x86_64-linux-gnu/libX11.so.6
No symbol table info available.
#7  0x00007f6a2aec2f3b in _XReply () from /usr/lib/x86_64-linux-gnu/libX11.so.6
No symbol table info available.
#8  0x00007f6a2aebea6d in XSync () from /usr/lib/x86_64-linux-gnu/libX11.so.6
No symbol table info available.
#9  0x00007f6a2ae9f790 in XCloseDisplay () from /usr/lib/x86_64-linux-gnu/libX11.so.6
No symbol table info available.
#10 0x0000000000400b2c in ?? ()
No symbol table info available.
#11 0x00007f6a2a88876d in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#12 0x0000000000400bf5 in ?? ()
No symbol table info available.
#13 0x00007fff7c288fa8 in ?? ()
No symbol table info available.
#14 0x000000000000001c in ?? ()
No symbol table info available.
#15 0x0000000000000001 in ?? ()
No symbol table info available.
#16 0x00007fff7c289f91 in ?? ()
No symbol table info available.
#17 0x0000000000000000 in ?? ()
No symbol table info available.