Oh and BTW the other thread (there are exactly two at that point) has always the same stack trace (so is probably just blocked at that select call):
Thread 2 (Thread 0x7fffe565d700 (LWP 5684)):
#0 0x00007ffff529d763 in select () at ../sysdeps/unix/syscall-template.S:82
#1 0x00007fffe573898a in NotifierThreadProc (clientData=<optimized out>) at /build/buildd/tcl8.5-8.5.11/unix/../unix/tclUnixNotfy.c:988
#2 0x00007ffff662fe9a in start_thread (arg=0x7fffe565d700) at pthread_create.c:308
#3 0x00007ffff52a43fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#4 0x0000000000000000 in ?? ()
Oh and BTW the other thread (there are exactly two at that point) has always the same stack trace (so is probably just blocked at that select call): unix/syscall- template. S:82 <optimized out>) at /build/ buildd/ tcl8.5- 8.5.11/ unix/.. /unix/tclUnixNo tfy.c:988 d700) at pthread_ create. c:308 unix/sysv/ linux/x86_ 64/clone. S:112
Thread 2 (Thread 0x7fffe565d700 (LWP 5684)):
#0 0x00007ffff529d763 in select () at ../sysdeps/
#1 0x00007fffe573898a in NotifierThreadProc (clientData=
#2 0x00007ffff662fe9a in start_thread (arg=0x7fffe565
#3 0x00007ffff52a43fd in clone () at ../sysdeps/
#4 0x0000000000000000 in ?? ()