The dbus problems are due to missing scm credentials sendmsg scm creds and socket credentials pflocal socket credentials for local sockets. There was also a problem with short timeout in select, but that has been solved in Debian by setting a minimum timeout of 1ms.

IRC, freenode, #hurd, 2011-11-26:

<antrik> BTW, how much effort is necessary to fix dbus?
<pinotree> basically, have pflocal know who's the sender
  (pid/uid/gid/groups) in the socket send op

IRC, freenode, #hurd, 2011-12-16:

<braunr> pinotree: what's the problem with dbus ?
<pinotree> braunr: select() returning 0 changed fd's with very short (eg <
  1ms) timeouts when there are actually events;

select.

<pinotree> and missing socket credentials

sendmsg scm creds.

<braunr> oh
<braunr> which socket creds interface ?
<pinotree> bsd, i.e. with SCM_CREDENTIALS payload for cmsg on
  {recv,send}msg()
<braunr> ok
<braunr> SCM_RIGHTS too ?
<braunr> the select issue seems weird though
<pinotree> hm no, that's for passing fd's to other processes
<braunr> is it specific to pflocal or does dbus use pfinet too ?
<pinotree> iirc on very short timeouts the application has no time waiting
  for the reply of servers
<braunr> i see
<pinotree> braunr: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=79358
<braunr> thanks
<pinotree> (the interesting messages are from #53 and on)
<braunr> 2000 eh ... :)
<braunr> hm i agree with neal, i don't understand why the timeout is given
  to the kernel as part of the mach_msg call

IRC, freenode, #hurd, 2011-12-20:

<braunr> hm, i don't see any occurrence of SCM_CREDENTIALS in dbus
<braunr> only SCM_RIGHTS
<pinotree> braunr: yes, that one
<braunr> oh
<braunr> i thought you said the opposite last time
<pinotree> dbus/dbus-sysdeps-unix.c, write_credentials_byte and
  _dbus_read_credentials_socket (with #define HAVE_CMSGCRED)
<braunr> hm
<braunr> which version ?
<braunr> i don't see anything in 1.4.16
<pinotree> 1.4.16
<braunr> grmbl
<braunr> ah, i see
<braunr> SCM_CREDS
<pinotree> if you want, i have a simplier .c source with it
<braunr> no i'm just gathering info
<pinotree> ok
<braunr> what's the deal with SCM_CREDS and SCM_CREDENTIALS ?
<braunr> bsd vs sysv ?
<braunr> oh, http://lists.debian.org/debian-hurd/2002/03/msg00135.html
<braunr> so we actually do want both SCM_CREDS and SCM_RIGHTS for debus
<braunr> dbus
<pinotree> SCM_RIGHTS is a different matter, it is for passing fd's
<braunr> yes
<braunr> but it's used by dbus
<braunr> so if we can get it, it should help too
<pinotree> there's a preliminary patch for it done by emilio time ago, and
  iirc it's applied to debian's glibc
<braunr> ah, he changed the libc
<braunr> right, that's the only sane way
<pinotree> iirc roland didn't like one or more parts of it (but i could be
  wrong)
<braunr> ok