On Sun, 2014-03-23 at 15:28 +0100, Thomas Gleixner wrote:
> On Sun, 23 Mar 2014, James Bottomley wrote:
> > On Sun, 2014-03-23 at 09:04 +0100, Thomas Gleixner wrote:
> > > On Sun, 23 Mar 2014, Tetsuo Handa wrote:
> > >
> > > > Thomas Gleixner wrote:
> > > > > But then systemd/udev mutters:
> > > > >
> > > > > "You migh be able to work around the timeout with udev rules and
> > > > > OPTIONS+="event_timeout=120", but that code was maybe never used
> > > > > or tested, so it might not work correctly." [1]
> > > > >
> > > > > AFAICT from the ubuntu bug system [2] nobody bothered even to try that.
> > > > >
> > > > > And if the udev/systemd event_timeout option is broken it's way better
> > > > > to fix that one instead of hacking random heuristics into the kernel.
> > > >
> > > > I haven't tried the event_timeout= option but I think it will not work.
> > > > The timeout is hard coded as shown below and there will be no chance for taking
> > > > the event_timeout= option into account.
> > > >
> > > > ---------- systemd-204/src/udev/udevd.c start ----------
> > > > (...snipped...)
> > > > /* check for hanging events */
> > > > udev_list_node_foreach(loop, &worker_list) {
> > > > struct worker *worker = node_to_worker(loop);
> > > >
> > > > if (worker->state != WORKER_RUNNING)
> > > > continue;
> > > >
> > > > if ((now(CLOCK_MONOTONIC) - worker->event_start_usec) > 30 * 1000 * 1000) {
> > >
> > > And because systemd has an immutable hardcoded random timeout we add
> > > another hardcoded random timeout into kthread_create() to work around
> > > that.
> > >
> > > How broken is that?
> > >
> > > And it seems other people have solved it:
> > >
> > > http://www.redhat.com/archives/lvm-devel/2013-September/msg00036.html
> >
> > I agree with Thomas. A hardcoded timeout is a systemd bug. However,
> > could I get confirmation, while you can use this bug to do it, that the
> > patch back in this thread actually fixes the crash when scsi_alloc_host
> > fails, that's the serious SCSI bug, in my view?
>
> Which patch, the one to kthread_create() or the one to SCSI?
The one to SCSI ... I'm only really interested in the oops when
scsi_host_alloc fails.
James
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