Re: please fix FUSION (Was:[v3.13][v3.14][Regression]kthread:makekthread_create()killable)

From: Thomas Gleixner
Date: Sun Mar 23 2014 - 04:04:38 EST


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

Thanks,

tglx
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