(gdb) thread apply all bt

Thread 2 (Thread -1210393696 (LWP 22977)):
#0  0xffffe410 in __kernel_vsyscall ()
#1  0xb7ea3321 in select () from /lib/tls/i686/cmov/libc.so.6
#2  0xb7dd9638 in usb_os_find_busses () from /lib/libusb-0.1.so.4
#3  0xb7f1ba30 in RD_do_read (timeout=0) at libusb.c:279
#4  0xb7f1bbef in RD_main (foo=0x0) at libusb.c:324
#5  0xb7db5504 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#6  0xb7eaa51e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread -1210390864 (LWP 22976)):
#0  0xffffe410 in __kernel_vsyscall ()
#1  0xb7db8816 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb7eb6a3d in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3  0xb7f1c503 in u_read_i (ps=0x8054738, buf=0x0, len=1, flags=1, timeout=0) at libusb.c:541
#4  0xb7f1c018 in u_poll (ps=0x8054738, timeout=0) at libusb.c:455
#5  0xb7f1a447 in pi_usb_accept (ps=0x8054738, addr=0x0, addrlen=0x0) at usb.c:423
#6  0xb7f44bbb in pi_accept_to (pi_sd=3, addr=0x0, addrlen=0x0, timeout=0) at socket.c:1139
#7  0x0804fc2a in plu_connect () at userland.c:80
#8  0x0804f66a in main (argc=5, argv=0xbfd1dd44) at pilot-xfer.c:2511