tor on SunOS: [err] Error from libevent: evport.c:425: Assertion evpd->ed_pending[i] == fd failed in evport_del

[ruebezahl]

Tor 0.3.3.7 (git-035a35178c92da94) running on SunOS with Libevent 2.1.8-stable, OpenSSL 1.0.2o, Zlib 1.2.11, Liblzma N/A, and Libzstd N/A.

(this error was also observed under tor 0.3.3.6 for about two weeks, no change with updating to 0.3.3.7)

every 10-20 minutes (sometimes longer) the process crashes with:

[err] Error from libevent: evport.c:425: Assertion evpd->ed_pending[i] == fd failed in evport_del

Contrary to tor crashes no libevent stacktrace is provided in default output.

The OS-Project under which the Service is running should have sufficent fd-ulimits:

ulimit -n
65536

Service privileges for the running User are pretty standard:

privileges='basic,net_privaddr'

[teor]

Can someone please triage this bug?
Is it a libevent bug, or is Tor using libevent wrong?

SunOS is an unsupported platform for Tor, because we don't have anyone who runs it, and we're not sure if we can write correct patches for it:
https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkTeam/SupportedPlatforms

So if it's a Tor bug, we will have to rely on a SunOS user to write a patch.

[nickm]

What version of libevent are you using? Did the same version work okay with Tor 0.3.2.x?

[ruebezahl]

as stated above: Libevent 2.1.8-stable, also also for 0.3.3.6 - Did not run the Node with 0.3.2.x - I can test another version of either libevent or tor if you like.

Also, a Illumos-Zone with gcc etc for compiling & testing can easily be provided, just say the word (and your ssh-pubkey ;) )

In regard to the "supported platforms" - document you linked, illumos is definitely not a "most weird old unix", the kernel build tor is running is 20180524. You can lookup some illumos distributions like SmartOS or OmniOS if you like. Just saying :)

[ruebezahl]

fyi: upgrade to to 0.3.3.8 did not change the behaviour

[ruebezahl]

upgrade to 0.3.3.9 did also not change the behaviour

[teor]

Please try running Tor 0.2.9 and Tor master, so that we can see if Tor introduced the bug in any supported release.

[teor]

You could also try logging the bug against libevent:
​https://github.com/libevent/libevent/issues

[teor]

These tickets need more information, so they can't be in 0.3.5.

[teor]

These open, non-merge_ready tickets can not get backported to 0.3.3, because 0.3.3 is now unsupported.

[teor]

Hmm, I guess they should still get 033-backport-unreached