Date: Mon, 8 Jan 2018 17:56:51 +0100
From: Willy Tarreau <w@1wt.eu>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de,
        gnomes@lxorguk.ukuu.org.uk, torvalds@linux-foundation.org
Subject: Re: [PATCH RFC 2/4] x86/arch_prctl: add ARCH_GET_NOPTI and
 ARCH_SET_NOPTI to enable/disable PTI
Message-ID: <20180108165651.GC10913@1wt.eu>
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 <20180108164900.GO32035@hirez.programming.kicks-ass.net>
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On Mon, Jan 08, 2018 at 05:49:00PM +0100, Peter Zijlstra wrote:
> On Mon, Jan 08, 2018 at 05:12:17PM +0100, Willy Tarreau wrote:
> > +		if (doit) {
> > +			if (arg2)
> > +				task_thread_info(task)->flags |= _TIF_NOPTI;
> > +			else
> > +				task_thread_info(task)->flags &= ~_TIF_NOPTI;
> 
> {set,clear}_thread_flag() please, the above is not SMP safe.

Oops, thank you. I initially thought about it initially but didn't
know the names of the functions to use, and have left it there
thinking I'd fix it later. Usual source of bugs :-/

Bah and I left my debugging printk() in the patch as well! I'll
rework this a bit.

Thanks,
Willy