Sandbox doesn't work with obfsproxy

When running tor [0.2.5.1-alpha-dev (git-a6b4934037d1308e)] with sandbox enabled and using obfsproxy [0.2.4] I get the following error:

(Sandbox) Caught a bad syscall attempt (syscall 0x2A)

after which tor terminates.

Trac:
Username: zoltan

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