Did a bit more reading into the root cause; seems to be that it is
undefined behavior in erlang when one opens a port multiple times with
the same fd. This is path that rabbitmq-server currently triggers, and
in _some_ versions of erlang this segfaults.
A standalone example of the faulty code in rabbitmq-server is:
erl -noshell -eval 'Port = open_port({fd, 0, 2}, [out]), Port2 =
open_port({fd, 2, 2}, [out]), port_command(Port, "a"), port_close(Port),
erlang:halt(10)'
Standalone test:
Trusty: OK, Xenial: segfault Yakkety: segfault, Zesty: OK
rabbitmq-server has offending code:
Trusty: yes Xenial: yes, Yakkety: yes, Zesty: no
Note: The rabbitmq-server offending code path is essentially anything
that uses the format_stderr(Fmt, Args) function helper function. The
testcase provided in #1 is just a single specifc instance that could
trigger the segfault. IOW, the bug is somewhat more broad of a bug than
that testcase and description, thus more interesting to SRU a fix into
Xenial/Yakkety.
As yakkety and xenial contain both a rabbitmq-server with the offending
code && an erlang that will segfault with it, we should SRU there.
While trusty contains the offending codepath 1) it cannot be triggered
with the erlang version in trusty (1.16.x) and 2) the proposed upstream
commit for the fix makes claim that it is safe with changes now made
erlang-17 or later, so this fix is not certain to not cause other issues
on trusty. IOW, best to leave trusty alone.
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https://bugs.launchpad.net/bugs/1634989
Title:
Segfault on rabbitmq-server start
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