multiple waiting requests and evdns_shutdown() cause SIGSEGV. about libevent

[nmathewson]

This looks okay to me. Merged in 2.0 and 2.1.

[yasuoka]

Thanks!

[yasuoka]

Sorry, I'd like you to reopen this issue since the previous patch fix the problem partially.

evdns has probe requests internally, those requests also had remained after evdns_shutdown() and they cause SIGSEGV. I think evdns_shutdown() should cancel those request.

New test program: evdns_test2.c

Test result on OpenBSD 5.4 amd64 + libevent -current(86665a5)

% env MALLOC_OPTIONS=J ./evdns_test2
[msg] Nameserver 127.0.0.1:53 has failed: request timed out.
[msg] All nameservers have failed
on_resolved()
on_resolved()
on_timeout() calling evdns_shutdown(1)
Bus error (core dumped)
%

Patch to fix: evdns_shutdown2.diff

Test result on OpenBSD 5.4 amd64 + libevent -current(86665a5) + patch

% env MALLOC_OPTIONS=J ./evdns_test2
[msg] Nameserver 127.0.0.1:53 has failed: request timed out.
[msg] All nameservers have failed
on_resolved()
on_resolved()
on_timeout() calling evdns_shutdown(1)
%

[nmathewson]

Merged that; thanks.