Python multiprocessing: Permission denied
linux, python
Solution
For POSIX semaphores to work, the users need r/w access to shared memory (`/dev/shm`).
Check the permissions to `/dev/shm`. On my laptop (Ubuntu) it looks like this:
$ ls -ld /dev/shm
drwxrwxrwt 2 root root 40 2010-01-05 20:34 shm
To permanently set the correct permissions (even after a reboot), add the following to your `/etc/fstab`:
none /dev/shm tmpfs rw,nosuid,nodev,noexec 0 0
Haven't tried this, just copied from a forum post.
Problem
I'm getting an error when trying to execute python program that uses multiprocessing package: ``` File "/usr/local/lib/python2.6/multiprocessing/__init__.py", line 178, in RLock return RLock() File "/usr/local/lib/python2.6/multiprocessing/synchronize.py", line 142, in __init__ SemLock.__init__(self, RECURSIVE_MUTEX, 1, 1) File "/usr/local/lib/python2.6/multiprocessing/synchronize.py", line 49, in __init__ sl = self._semlock = _multiprocessing.SemLock(kind, value, maxvalue) OSError: [Errno 13] Permission denied ``` It looks like the user doesn't have permission to access shared memory. When executing with root privileges it works fine. Is there any solution to run it as normal user(not root)? Python version 2.6.2 , OS is Linux 2.6.18 (CentOS release 5.4) and it's VPS machine.