John: it would be interesting to try to determine whether that hang has the same root cause as the cmake and boehm-gc hangs, ie the thing that is supposed to post the futex is a signal handler whose signal comes in either just before or during the syscall [either way, the emulated code for the handler won't be able to run until the syscall returns, which it never does].
John: it would be interesting to try to determine whether that hang has the same root cause as the cmake and boehm-gc hangs, ie the thing that is supposed to post the futex is a signal handler whose signal comes in either just before or during the syscall [either way, the emulated code for the handler won't be able to run until the syscall returns, which it never does].