Re: [patch 0/6] 3.14-rt1 fixes

[Mike Galbraith <umgwanakikbuti@gmail.com>]

On Sat, 2014-05-03 at 14:31 +0200, Nicholas Mc Guire wrote: 
> On Sat, 03 May 2014, Mike Galbraith wrote:

> > If this is in fact safe, you should be able to move each and every
> > migrate_disable() to post acquisition.
> 
> yup

Having just seen working -> brick transition, color me skeptical.

> > I have a virtual nickle that
> > says your box will have a severe allergic reaction to such a patch.
> >
> Actually that is what the pushdowns in the read_lock/write_lock api did and
> I did not notice any of the systems having problems with that.

If you had tested hotplug, you would have met the deadlock, and would
have verified that the change to read_lock() was the culprit instead of
me doing that.  Steven also verified that.  You too can flip back and
forth, drive boxen into the wall as many times as it take to convince
yourself that that change really really did induce the breakage.

I'll read the rest later, I'm getting all grumpy.

-Mike