Crash SIGSEGV about frostwire-jlibtorrent

[aldenml]

Is this always happening to you? could you provide a minimal program to reproduce it?

[gubatron]

also, what version of libtorrent are you running?

[WhiteTrashLord]

I test with jlibtorrent-linux-1.1.0.19.jar.

I saw this crash only 1 time so far.
Sorry, I don't know how to reproduce it.

Where does the problem occur? com.frostwire.jlibtorrent.swig.libtorrent_jni.torrent_handle_info_hash?

I don't know much about JNI :(

[aldenml]

JNI is very sensitive to memory management issues. I will keep this open in case we start to get this errors

[WhiteTrashLord]

Unfortunately I see a lot of crashes. Older versions might be more stable?

In my test code I get a list of torrents with getSwig().get_torrents() and request several fields from every torrent.

I frequently get a new list of torrents and iterate through it.

[aldenml]

Older version if anything are more unstable and with more bugs from libtorrent itself. Can't give you an estimate, but I'm reviewing this (and the others).

[WhiteTrashLord]

I think I saw many more crashes when I worked on the session concurrently with several threads. I tried to reduce the concurrency which made things better.
You tried to make anything thread-safe?

Probably the safest way is to always use only listeners, or?

[aldenml]

I wouldn't treat anything thread-safe unless stated otherwise, specially Session since it holds a lot of states (mutable data). Listeners and alerts are the way to interact with the session. A TorrentHandle coming from an alert is a very delicate object and should be used for the smaller amount of time and never shared to other threads.

[WhiteTrashLord]

What about removing and adding a torrent? I think at least removing can cause a lot of troubles if the AlertLoop-Thread works on a handle of a torrent which was just deleted.

Is it necessary to start alertsLoop() in the session constructor? I think I would start it once the first listener was added.

Currently I am thinking about modifying the Session-alertsLoop so I can run also my own code on this thread. Do you think this is a good idea?

[aldenml]

I need to think a little more about concurrency issues while removing a torrent.

AlertsLoop and Session are there to provide an out-of-the-box solution. I personally don't see an advantage of no starting it in the constructor (you will need it pretty soon anyway).

Can say without knowing what's your modification. If you don't mind sharing it.

[aldenml]

@WhiteTrashLord reopening for more review.