[systemd-devel] avahi disconnects from bus with kdbus

[David Herrmann]

Hi Daniel!

On Fri, Feb 13, 2015 at 1:16 PM, David Herrmann <dh.herrmann at gmail.com> wrote:
> Hi
>
> On Thu, Feb 12, 2015 at 11:32 PM, Daniel Buch <boogiewasthere at gmail.com> wrote:
>> Hi again,
>>
>> I found another problem, again with avahi-daemon but in combination with
>> Telepathy haze.
>> feb 13 08:26:39 dbuch-laptop systemd-coredump[1211]: Process 1167
>> (telepathy-haze) of user 1000 dumped core.
>>
>>                                                      Stack trace of thread
>> 1167:
>>                                                      #0  0x00007fe0c9557ae0
>> g_logv (libglib-2.0.so.0)
>>                                                      #1  0x00007fe0c9557d1f
>> g_log (libglib-2.0.so.0)
>>                                                      #2  0x000000000041261c
>> n/a (telepathy-haze)
>>                                                      #3  0x00007fe0c955091d
>> g_main_context_dispatch (libglib-2.0.so.0)
>>                                                      #4  0x00007fe0c9550cf8
>> n/a (libglib-2.0.so.0)
>>                                                      #5  0x00007fe0c9551022
>> g_main_loop_run (libglib-2.0.so.0)
>>                                                      #6  0x00007fe0c9214631
>> tp_run_connection_manager (libtelepathy-glib.so.0)
>>                                                      #7  0x000000000040e73b
>> n/a (telepathy-haze)
>>                                                      #8  0x00007fe0c8b1e800
>> __libc_start_main (libc.so.6)
>>                                                      #9  0x000000000040e7ad
>> n/a (telepathy-haze)
>
> This looks like a bug in telepathy, properly triggered by a dbus
> error. This should be fixed upstream, but..
>
>> feb 13 08:26:42 dbuch-laptop systemd[642]: Starting DBUS1:
>> org.freedesktop.Telepathy.ConnectionManager.haze...
>> feb 13 08:26:42 dbuch-laptop systemd[642]: Started DBUS1:
>> org.freedesktop.Telepathy.ConnectionManager.haze.
>> feb 13 08:26:42 dbuch-laptop systemd[1]: Starting Avahi mDNS/DNS-SD Stack...
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Found user 'avahi' (UID 84)
>> and group 'avahi' (GID 84).
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Successfully dropped root
>> privileges.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: avahi-daemon 0.6.31
>> starting up.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Successfully called
>> chroot().
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Successfully dropped
>> remaining capabilities.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Loading service file
>> /services/sftp-ssh.service.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Process 313 died: No such
>> process; trying to remove PID file. (/var/run/avahi-daemon//pid)
>> feb 13 08:26:42 dbuch-laptop systemd[1]: Started Avahi mDNS/DNS-SD Stack.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Loading service file
>> /services/ssh.service.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Joining mDNS multicast
>> group on interface wlp3s0.IPv4 with address 192.168.1.2.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: New relevant interface
>> wlp3s0.IPv4 for mDNS.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Network interface
>> enumeration completed.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Registering new address
>> record for fe80::eab1:fcff:fec4:eae1 on wlp3s0.*.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Registering new address
>> record for 192.168.1.2 on wlp3s0.IPv4.
>> feb 13 08:26:42 dbuch-laptop avahi-daemon[1217]: Registering HINFO record
>> with values 'X86_64'/'LINUX'.
>> feb 13 08:26:42 dbuch-laptop systemd-bus-proxyd[329]: Failed to send message
>> to bus: Operation not permitted
>
> ..this might be what triggered it. It'd be interesting to see which
> message was refused here. I'll see whether we can make the bus-proxy
> more verbose on EPERM.

This issue should be fixed with systemd-git and kdbus-git:
 - systemd-bus-proxyd no longer closes the connection on EPERM, but
forwards the error
 - kdbus no longer generates EPERM for unicast-signals

The bus-proxyd fix should make sure that avahi continues running, the
kdbus fix should make sure that EPERM is no longer generated for
avahi.

Thanks
David