Clients seeing EPIPE, dbus-daemon 1.8.16, how to debug?

[Andrey Sidorov]

I've seen similar problem - https://github.com/sidorares/node-dbus/issues/82

Existed in 1.8.10  and disappeared in 1.8.16
When daemon is unhappy about serialisation being invalid I usually get
disconnect with proper stream closing, not EPIPE

On Wed, Jun 3, 2015 at 6:37 AM, Thiago Macieira <thiago at kde.org> wrote:

> On Monday 01 June 2015 21:21:16 Chris Morgan wrote:
> > Hello.
> >
> > I'm using dbus-daemon on a systemd distro built under yocto on an arm
> > system, a BBB (1GHz Arm), 512MB ram, emmc.
> >
> > At startup we've got two clients, one c# using dbus-sharp, and another
> > nodejs using node-dbus (https://github.com/sidorares/node-dbus) that
> > are both seeing EPIPE from the dbus client socket as reported via
> > strace.
>
> For real pipes, EPIPE indicates that you're writing while there's no pipe
> reader. For sockets, that happens only when a connected socket's peer has
> shut
> down reception. In other words, the socket has disconnected.
>
> dbus-daemon only disconnects you if you send invalid stuff. So I advise
> you to
> check those two bindings for protocol correctness.
>
> > I'm guessing that the high cpu and io load at startup may be the cause
> > of the issue. Those clients are relatively heavy to startup, one being
> > mono, the other node. This particular issue isn't seen on the desktop
> > under F21 or Arch with the same software.
>
> No, that can't be it. If the socket never connected, you'd get ENOTCONN,
> not
> EPIPE.
>
> > Is there some way to debug the reason behind the EPIPE from the
> > dbus-daemon side? I tried compiling with the --enable-verbose-tracing
> > and enabling DBUS_VERBOSE=1 but that produces a ton of output that
> > seems unrelated to the EPIPE issue.
>
> The message failed to parse. Use strace on your application and capture the
> all the messages sent after the last time the bus sent anything to you.
> One of
> those messages is invalid.
>
> --
> Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
>    Software Architect - Intel Open Source Technology Center
>       PGP/GPG: 0x6EF45358; fingerprint:
>       E067 918B B660 DBD1 105C  966C 33F5 F005 6EF4 5358
>
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