hs-v3: Segfault in hs_circ_service_get_established_intro_circ()
Reported by atagar on IRC: ``` <+atagar> Looks like stem's jenkins runs are presently failing due to tor segfaults: https://paste.debian.net/plain/1119133 ``` The report: ``` ... Dec 02 17:03:09.077 [notice] Configured to measure directory request statistics, but no GeoIP database found. Please specify a GeoIP database using the GeoIPFile option. Dec 02 17:03:09.085 [warn] Controller gave us config lines that didn't validate: Unknown option 'bombay'. Failing. Dec 02 17:03:09.085 [warn] Tor is currently configured as a relay and a hidden service. That's not very secure: you should probably run your hidden service in a separate Tor process, at least -- see https://trac.torproject.org/8742 Dec 02 17:03:09.088 [notice] Configured to measure directory request statistics, but no GeoIP database found. Please specify a GeoIP database using the GeoIPFile option. Dec 02 17:03:09.225 [warn] Failed to find node for hop #1 of our path. Discarding this circuit. ============================================================ T= 1575306189 Tor 0.4.3.0-alpha-dev died: Caught signal 11 /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(+0x21ceb5)[0x56360d945eb5] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(hs_circ_service_get_established_intro_circ+0x27)[0x56360d8327e7] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(hs_circ_service_get_established_intro_circ+0x27)[0x56360d8327e7] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(hs_service_run_scheduled_events+0x14ff)[0x56360d849ccf] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(+0x72961)[0x56360d79b961] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(+0x762f3)[0x56360d79f2f3] /usr/lib/x86_64-linux-gnu/libevent-2.0.so.5(event_base_loop+0x6a0)[0x7f6688b925a0] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(do_main_loop+0xe5)[0x56360d79e565] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(tor_run_main+0x122d)[0x56360d78ba2d] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(tor_main+0x3a)[0x56360d7891da] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(main+0x19)[0x56360d788d59] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf1)[0x7f66873e72e1] /srv/jenkins-workspace/workspace/stem-tor-ci/RESULT/tor(_start+0x2a)[0x56360d788daa] ```
issue