The Dropbox Linux client is hanging during startup on my Red Hat Enterprise Linux (RHEL) 6 box. It has worked on this machine before, and unfortunately I don't know what changed now. I have tried wiping out my "~/.dropbox" and "~/.dropbox-dist" directories, and using a fresh download of the client, but the hang persists. The same problem appears using both the 3.0.3 stable build as well as the 3.1.261 experimental build.
Tracing with "strace" reveals that the hang is in a call to "futex(0x295b1e0, FUTEX_WAIT_PRIVATE, 0, NULL)". Attaching a debugger to the hung process shows that we are down in some Python code. Most of the stack frames are either "PyEval_EvalCodeEx()" or "PyEval_EvalFrameEx()". The innermost stack frame is "sem_wait()", called from "PyThread_acquire_lock()".
I'm at a loss how to work around this or debug it further. Any suggestions as to how I can get my Dropbox client back up and running?