[sr-dev] [kamailio/kamailio] Deadlocks after ungracefully terminated TLS connections (#2395)

[Laszlo]

OK, this turns out to be a lot more complicated. I'll try to describe as accurately as possible.

Turns out SSL support was already disabled on the server-side, so in all above examples there was no SSL used for the database connection. Although that doesn't rule out libssl still being involved in the db code, to _try_ to negotiate a SSL connection.

I was able to upgrade to Kamailio 5.3 without any problems, with exactly the same behavior as before; able to reproduce both failure modes.

With `modparam("db_mysql", "opt_ssl_mode", 1)` I can still easily reproduce failure mode 1.

I'm struggling to generate "accurate" backtraces for that, because either I'm crazy, or Kamailio keeps on "fixing itself" at _exactly_ the moment I decide to run `pstrap`. It can be frozen for minutes, not responding to any TCP socket at all, then suddenly in the middle of the gdb process print a bunch of messages like "tcpconn_1st_send(): connect 157.245.69.206:40573 failed (RST) Connection refused" then continue to function again.

Nonetheless, even with `modparam("db_mysql", "opt_ssl_mode", 1)` I see libmysqlclient in the backtrace coming from various ssl functions, e.g.

```
#3  0x00007fe9a9c87d30 in ?? () from /usr/lib/x86_64-linux-gnu/libmysqlclient.so.20
#4  0x00007fe9a9275c63 in ssleay_rand_add (buf=0x7ffcf0a04b18, num=8, add=0) at md_rand.c:230
```

Finally, so far I'm completely unable to reproduce the issue when `db_mysql.so` is not loaded! Looks like having both db_mysql.so and tls.so loaded causes some kind of conflict..

That's a lot of input - does this help and/or is there any avenue you'd like me to debug further?

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/kamailio/kamailio/issues/2395#issuecomment-656150321
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.kamailio.org/pipermail/sr-dev/attachments/20200709/8e98beb8/attachment.htm>