Re: [PATCH] Revert "exec: make de_thread() freezable (was: Re: Linux 4.20-rc4)

[Pavel Machek <pavel@ucw.cz>]

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On Mon 2018-12-03 13:38:57, Michal Hocko wrote:
> On Mon 03-12-18 13:31:49, Oleg Nesterov wrote:
> > On 12/03, Michal Hocko wrote:
> > >
> > > Now, I wouldn't mind to revert this because the code is really old and
> > > we haven't seen many bug reports about failing suspend yet. But what is
> > > the actual plan to make this work properly?
> > 
> > I don't see a simple solution...
> > 
> > But we need to fix exec/de_thread anyway, then we can probably reconsider
> > this patch.
> 
> My concern is that de_thread fix might be too disruptive for stable
> kernels while we might want to have a simple enough fix for the the
> suspend issue in the meantime. That was actually the primary reason I've
> acked the hack even though I didn't like it.

Do we care about failing sleep in stable? Does someone hit the issue there?

This sounds like issue only Android is hitting, and they run very
heavily patched kernels, far away from mainline or stable.

> So can we find a way to shut the lockdep up when this is not really a
> deadlock?  Or maybe this really is one and then we need a real fix for
> stable as well.

Shutting up the lockdep is of course possible...

...but lets first see what good solution looks like.
									Pavel
-- 
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