[mythtv] Unresponsive BE

John P Poet jppoet at gmail.com
Wed Nov 17 16:19:13 UTC 2010

On Wed, Nov 17, 2010 at 4:50 AM, warpme <warpme at o2.pl> wrote:
> Hi,
> I'm using 0.24-fixes 27235 with 2xDVB-S2 tuners. Im wonder is Dough's comment in:
> http://www.gossamer-threads.com/lists/mythtv/dev/450589?search_string=deadlock;#450589
> (see below) is still valid ?
> I have constant problems with unresponsive backend when tuning fails on my DVB-S2 tuners.
> In such case frontend reports:
> 2010-11-16 23:43:29.326 MythSocket(9056088:61): readStringList: Error, timed out after 60000 ms.
> 2010-11-16 23:43:29.326 Protocol version check failure.
>                        The response to MYTH_PROTO_VERSION was empty.
>                        This happens when the backend is too busy to respond,
>                        or has deadlocked in due to bugs or hardware failure.
> 2010-11-16 23:43:29.326 RemoteEncoder::Setup(): Failed to connect to backend
> 2010-11-16 23:43:29.326 RemoteEncoder::SendReceiveStringList(): Failed to reconnect with backend.
> Issue is really annoying as for user, BE behaves like dead for FE requests (process restart is needed).
> Here is relevant part of Doug comment:
> "...............
> The problem is that in the connectionClosed callback, a lock is used which
> is also used in many other places when iterating over the currently opened
> sockets. If socket operations are done while this lock is held, and the
> callback ends up getting called, it will deadlock. The conclusion is that it
> is not safe to perform socket operations when this lock is held.
> --
> Douglas Paul

I don't know if Doug's problem matches yours.

To diagnose your problem, we would need to see a lot more information.
 You have posted what happens after the problem, but we would need to
see what happened to cause the problem.  Please post a complete
"mythbackend -v record,channel" log.


A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

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