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I'm running tor on Gentoo Hardened. The bug exists in 0.2.6.7 and 0.2.7.1-alpha. tor crashes within seconds of starting, before any clients can connect I think.

Jul 14 13:13:07.000 [notice] Tor 0.2.7.1-alpha (git-df76da0f3bfd6897) opening log file.
Jul 14 13:13:07.182 [notice] Tor v0.2.7.1-alpha (git-df76da0f3bfd6897) running on Linux with Libevent 2.0.22-stable, OpenSSL 1.0.1p and Zlib 1.2.8.
Jul 14 13:13:07.182 [notice] Tor can't help you if you use it wrong! Learn how to be safe at https://www.torproject.org/download/download#warning
Jul 14 13:13:07.182 [notice] This version is not a stable Tor release. Expect more bugs than usual.
Jul 14 13:13:07.182 [notice] Read configuration file "/etc/tor/torrc".
Jul 14 13:13:07.187 [notice] Opening Socks listener on 127.0.0.1:9050
Jul 14 13:13:07.187 [notice] Opening Socks listener on 127.0.0.1:9056
Jul 14 13:13:07.187 [notice] Opening Socks listener on 127.0.0.1:9055
Jul 14 13:13:07.187 [notice] Opening Control listener on 127.0.0.1:9015
Jul 14 13:13:07.000 [notice] Parsing GEOIP IPv4 file /usr/share/tor/geoip.
Jul 14 13:13:07.000 [notice] Parsing GEOIP IPv6 file /usr/share/tor/geoip6.
Jul 14 13:13:07.000 [notice] Bootstrapped 0%: Starting

============================================================ T= 1436875987
(Sandbox) Caught a bad syscall attempt (syscall socket)
/usr/bin/tor(+0x142148)[0x4bb7bc8148]
/lib64/libc.so.6(socket+0x7)[0x3adc706ea07]
/lib64/libc.so.6(socket+0x7)[0x3adc706ea07]
/lib64/libc.so.6(+0xf16a0)[0x3adc70686a0]
/lib64/libc.so.6(__vsyslog_chk+0x3ef)[0x3adc7068aff]
/lib64/libc.so.6(__syslog_chk+0x89)[0x3adc7068df9]
/usr/bin/tor(+0x135bb0)[0x4bb7bbbbb0]
/usr/bin/tor(tor_log+0xd0)[0x4bb7bbc680]
/usr/bin/tor(control_event_bootstrap+0x1e4)[0x4bb7b7ba74]
/usr/bin/tor(do_main_loop+0x84)[0x4bb7abe234]
/usr/bin/tor(tor_main+0x16c5)[0x4bb7ac1225]
/lib64/libc.so.6(__libc_start_main+0x114)[0x3adc6f97134]
/usr/bin/tor(+0x34519)[0x4bb7aba519]

$ uname -r
3.18.9-hardened

This bug has been reported downstream: https://bugs.gentoo.org/show_bug.cgi?id=550302. It occurs with the following torrc:

#
# Minimal torrc so tor will work out of the box
#
User tor
PIDFile /var/run/tor/tor.pid
Log notice syslog
Log notice file /var/log/tor/log
DataDirectory /var/lib/tor/data
SandBox 1

SocksPort 9050
SocksPort 9056 IsolateDestAddr IsolateDestPort
SocksPort 9055

ControlPort 9015
CookieAuthentication 1

By commenting out "Sandbox 1" or unsetting it, tor will obviously run without crashing.