Upgrading libevent based TCP server implementation from commit id 665d79f1 to ec8d7a5a results in random crashes

[mareksm]

FYI: The server code did not change - it is running stable under various loads on commit id 665d79f (or earlier). After libevent upgrade to commit id ec8d7a5 it randomly crashes. Can't upload stack trace nor share server code unfortunately.
OS: RHEL8, non-ssl sockets only.

[mareksm]

From the server perspective, only concerning changes (going from one commit to the other) are in bufferevent_pair.c, bufferevent_ssl.c, bufferevent_filter.c, evthread.c and evutil_time.c.

[mareksm]

Something has changed going from earlier (stable) commit id to the newer one. Could it be updates involving EVUTIL_ASSERT, BEV_IS_FILTER changes in those source files?

[azat]

There is not too much can be done without stacktrace or reproducer, please provide one or another.
You can configure your server to preserve core dumps and compile with -O2 -g3
And/or run under ASAN

[azat]

Something has changed going from earlier (stable) commit id to the newer one. Could it be updates involving EVUTIL_ASSERT, BEV_IS_FILTER changes in those source files?

I don't see how it is possible, now upcast() cannot return NULL, but everywhere it is used now it dereference the pointer without check anyway

[mareksm]

The server is not using http module from libevent.
No problem with the server when running with commit id 665d79f