linux-kernel - Re: please fix FUSION (Was:[v3.13][v3.14][Regression]kthread:makekthread

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.02.1403231524100.18573@ionos.tec.linutronix.de>
Date:	Sun, 23 Mar 2014 15:28:11 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	James Bottomley <James.Bottomley@...senPartnership.com>
cc:	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>, oleg@...hat.com,
	joseph.salisbury@...onical.com, Nagalakshmi.Nandigama@....com,
	Sreekanth.Reddy@....com, rientjes@...gle.com,
	akpm@...ux-foundation.org, torvalds@...ux-foundation.org,
	tj@...nel.org, linux-kernel@...r.kernel.org,
	kernel-team@...ts.ubuntu.com, linux-scsi@...r.kernel.org,
	thenzl@...hat.com
Subject: Re: please fix FUSION
 (Was:[v3.13][v3.14][Regression]kthread:makekthread_create()killable)

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?

Thanks,

	tglx



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/