Re: [Monotone-devel] Stalled server

[Timothy Brownawell]

On 1/6/2010 7:21 AM, Richard Levitte wrote:
> Since about a week, I've run a debug variant of the server on
> monotone.ca...  It stalled today with the following backtrace:
>
> (gdb) bt
> #0  0xb7fe1424 in __kernel_vsyscall ()
> #1  0xb7a055b1 in select () from /lib/i686/cmov/libc.so.6
> #2  0x08396185 in Netxx::Probe_impl::probe (this=0xac85c50, timeout=..., rt=2)
>      at netxx/probe_select.cxx:221
> #3  0x0839df72 in Netxx::Socket::writable (this=0xac85c48, timeout=...)
>      at netxx/socket.cxx:301
> #4  0x0839e282 in Netxx::Socket::write (this=0xac85c48, buffer=0xcbd799c,
>      length=451, timeout=...) at netxx/socket.cxx:178
> #5  0x08398e4f in Netxx::Stream::write (this=0xb4bf720, buffer=0xcbd799c,
>      length=451) at netxx/stream.cxx:132

When we get a new connection, it does get set non-blocking but we also 
tell netxx to give it a long timeout, which it does by select()ing on 
it. So apparently we get a spurious 'writeable' from the main select() 
loop, and then the select() when trying to write times out.

I think it just needs something other than 'timeout' below, but I need 
to run to work right now.

$ grep -n -A1 -B6 "new Netxx::Stream" network/listener.cc
65-      // 'false' here means not to revert changes when the SockOpt
66-      // goes out of scope.
67-      Netxx::SockOpt socket_options(client.get_socketfd(), false);
68-      socket_options.set_non_blocking();
69-
70-      shared_ptr<Netxx::Stream> str =
71:        shared_ptr<Netxx::Stream>(new 
Netxx::Stream(client.get_socketfd(),
72-                                                    timeout));