[Pkg-xfce-devel] Bug#829557: Bug#829557: Bug#829557: firefox: error box at start-up / D-BUS related issue

[Yves-Alexis Perez]

[adding Robert and the launchpad bug to CC]

On Mon, 2016-07-11 at 13:03 +0200, Yves-Alexis Perez wrote:
> On Mon, 2016-07-11 at 11:46 +0200, Yves-Alexis Perez wrote:
> > > I wonder whether there are other reasons why epoll_ctl can report
> > > EINVAL?
> > 
> > The syscall source code is at http://lxr.free-electrons.com/source/fs/even
> > tp
> > ol
> > l.c#L1849 and it seems EINVAL is used as a default error case at various
> > places, so maybe.
> > >  
> > > I also wonder whether the new lightdm is starting dbus-launch with a
> > > different value for some arbitrary kernel limit, or whether your
> > > previous
> > > session leaked some fds resulting in dbus-launch coming up with 90% of
> > > an arbitrary limit already in use, or something like that?
> > 
> > For what it's worth, after closing the first session there's no process
> > running under my uid. I'll try to check the limits in 75dbus to see if
> > they
> > differ.
> 
> Some more investigation: I've done a bisect in lightdm and the offending
> commit is https://bazaar.launchpad.net/~lightdm-team/lightdm/1.18/revision/2
> 31
> 9 which is a somehow large refactoring, I didn't yet identify what could be
> the problem there (but reported that upstream as well).
> 
> I've checked the currently opened file descriptors when when starting the
> session (I've added an ls -l /proc/self/fd in 75dbus..) and here are the
> results (don't bother about the PIDs, the “first” login was after a lightdm
> restart after the “second” login).
> 
> For the first login:
> 
> + ls -l /proc/self/fd
> total 0
> lr-x------ 1 corsac corsac 64 Jul 11 12:56 0 -> /dev/null
> l-wx------ 1 corsac corsac 64 Jul 11 12:56 1 -> /home/corsac/.xsession-
> errors
> l-wx------ 1 corsac corsac 64 Jul 11 12:56 2 -> /home/corsac/.xsession-
> errors
> lr-x------ 1 corsac corsac 64 Jul 11 12:56 3 -> /proc/30014/fd
> 
> For the second:
> 
> + ls -l /proc/self/fd
> total 0
> lr-x------ 1 corsac corsac 64 Jul 11 12:56 0 -> /proc/29846/fd
> l-wx------ 1 corsac corsac 64 Jul 11 12:56 1 -> /home/corsac/.xsession-
> errors
> l-wx------ 1 corsac corsac 64 Jul 11 12:56 2 -> /home/corsac/.xsession-
> errors
> 
> So it seems stdin is closed for the second login. Could it break dbus-
> launch/dbus-daemon somehow?

Looking at the 2319 revision in lightdm it seems that greeter_start() closes
the two file descriptors and that looks spurious. Digging a little bit more
reveals https://bazaar.launchpad.net/~lightdm-team/lightdm/1.18/revision/2327 
which seems to fix the problem indeed.

I'm uploading a packaged including the patch asap. 

Robert, you might want to release an 1.18.3 soon, I guess we're not the only
ones impacted.

Simon, I'm not sure if it's something worth investigating/fixing in dbus, so
I'll let you handle from there, I guess.

Thanks everyone for the help.

Regards,
-- 
Yves-Alexis
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