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Date:   Tue, 28 Feb 2023 19:14:07 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Helge Deller <deller@gmx.de>
Cc:     linux-arch@vger.kernel.org, linux-parisc@vger.kernel.org
Subject: Re: [PATCH 08/10] parisc: fix livelock in uaccess
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On Tue, Feb 28, 2023 at 07:26:48PM +0100, Helge Deller wrote:

> I can test both parisc32 and parisc64.
> 
> > 	Just to confirm: your "can be killed with ^C" had been on the
> > mainline parisc kernel (with userfaultfd enable, of course, or it wouldn't
> > hang up at all), right?
> 
> It was a recent mainline kernel with your patch.

Er...  Reproducer *is* supposed to block; the bug is that on the kernel
without this patch it would (AFAICS) be impossible to kill - not even
with kill -9.  With bug fixed the behaviour should be "blocks and is
killable", i.e. what you've reported.

What does it do on unpatched kernel?  *IF* the big is there, it would
block and be unkillable by any means.  Could you verify that?