@Carl Love 

The code is several thousand lines long, but does not contain any calls to Maple's Mutex/Threading

routines. A futex is a "Fast user-space mutex" (very linux-specific), with a corresponding system

call. So this looks like a deadlock in some lower-level C(?) -code.

The backtrace obtained by attaching gdb to a hanging process is e.g.:

#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f1299e30dda in ?? () from /software/maple/maple18/bin.X86_64_LINUX/libmaple.so
#2  0x00007f1299e2b6d5 in ?? () from /software/maple/maple18/bin.X86_64_LINUX/libmaple.so

Best regards,

Matthias