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Date: Fri, 29 Apr 2016 15:18:22 -0500
From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Jessica Yu <jeyu@redhat.com>, Jiri Kosina <jikos@kernel.org>,
 Miroslav Benes <mbenes@suse.cz>, Ingo Molnar <mingo@redhat.com>,
 Peter Zijlstra <peterz@infradead.org>,
 Michael Ellerman <mpe@ellerman.id.au>,
 Heiko Carstens <heiko.carstens@de.ibm.com>, live-patching@vger.kernel.org,
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 Vojtech Pavlik <vojtech@suse.com>, Jiri Slaby <jslaby@suse.cz>,
 Petr Mladek <pmladek@suse.com>,
 Chris J Arges <chris.j.arges@canonical.com>,
 Andy Lutomirski <luto@kernel.org>
Subject: Re: [RFC PATCH v2 09/18] livepatch/x86: add TIF_PATCH_PENDING thread
 flag
Message-ID: <20160429201822.rj5hbkfkjgrdxlz6@treble>
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On Fri, Apr 29, 2016 at 11:08:04AM -0700, Andy Lutomirski wrote:
> On Thu, Apr 28, 2016 at 1:44 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> > Add the TIF_PATCH_PENDING thread flag to enable the new livepatch
> > per-task consistency model for x86_64.  The bit getting set indicates
> > the thread has a pending patch which needs to be applied when the thread
> > exits the kernel.
> >
> > The bit is placed in the least-significant word of the thread_info flags
> 
> NAK to that part.
> 
> The least-significant word thing is a huge hack that has gotten out of
> control.  Please add the thing explicitly to all relevant masks.

Yeah, it is quite dangerous.  I'll make it explicit, and make all the
other _TIF_ALLWORK_MASK flags explicit while I'm at it.

-- 
Josh