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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
Date: Mon, 8 Jan 2018 17:56:51 +0100	[thread overview]
Message-ID: <20180108165651.GC10913@1wt.eu> (raw)
In-Reply-To: <20180108164900.GO32035@hirez.programming.kicks-ass.net>

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

  reply	other threads:[~2018-01-08 16:57 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-08 16:12 [PATCH RFC 0/4] Per-task PTI activation Willy Tarreau
2018-01-08 16:12 ` [PATCH RFC 1/4] x86/thread_info: add TIF_NOPTI to disable PTI per task Willy Tarreau
2018-01-08 16:57   ` Thomas Gleixner
2018-01-08 17:03     ` Willy Tarreau
2018-01-08 17:14       ` Ingo Molnar
2018-01-08 16:12 ` [PATCH RFC 2/4] x86/arch_prctl: add ARCH_GET_NOPTI and ARCH_SET_NOPTI to enable/disable PTI Willy Tarreau
2018-01-08 16:49   ` Peter Zijlstra
2018-01-08 16:56     ` Willy Tarreau [this message]
2018-01-08 17:02   ` Thomas Gleixner
2018-01-08 17:10     ` Willy Tarreau
2018-01-08 17:17     ` Ingo Molnar
2018-01-08 17:26       ` Thomas Gleixner
2018-01-08 17:46         ` Ingo Molnar
2018-01-08 17:05   ` Ingo Molnar
2018-01-08 17:19     ` Peter Zijlstra
2018-01-08 17:26       ` Ingo Molnar
2018-01-08 17:50   ` Borislav Petkov
2018-01-08 17:54   ` Linus Torvalds
2018-01-08 18:22     ` Willy Tarreau
2018-01-08 20:49       ` Thomas Gleixner
2018-01-08 21:03         ` Willy Tarreau
2018-01-08 20:35     ` Willy Tarreau
2018-01-08 16:12 ` [PATCH RFC 3/4] x86/pti: don't mark the user PGD with _PAGE_NX Willy Tarreau
2018-01-08 17:03   ` Dave Hansen
2018-01-08 17:17     ` Willy Tarreau
2018-01-08 17:23       ` Dave Hansen
2018-01-08 17:30         ` Peter Zijlstra
2018-01-08 17:49           ` Willy Tarreau
2018-01-08 17:21     ` Ingo Molnar
2018-01-08 23:05     ` Andy Lutomirski
2018-01-08 23:09       ` Kees Cook
2018-01-09  4:22       ` Willy Tarreau
2018-01-08 17:05   ` Thomas Gleixner
2018-01-08 17:28     ` Dave Hansen
2018-01-08 17:50       ` Ingo Molnar
2018-01-08 18:25         ` Alan Cox
2018-01-08 18:35           ` Ingo Molnar
2018-01-08 18:35           ` Linus Torvalds
2018-01-08 18:44         ` Dave Hansen
2018-01-08 16:12 ` [PATCH RFC 4/4] x86/entry/pti: don't switch PGD on tasks holding flag TIF_NOPTI Willy Tarreau
2018-01-08 17:11   ` Ingo Molnar
2018-01-08 17:20   ` Dave Hansen
2018-01-08 18:12     ` Willy Tarreau
2018-01-08 23:01   ` Andy Lutomirski
2018-01-08 16:59 ` [PATCH RFC 0/4] Per-task PTI activation Dave Hansen
2018-01-08 17:06   ` Willy Tarreau
2018-01-08 17:17     ` Dave Hansen
2018-01-08 17:13   ` Ingo Molnar
2018-01-09 15:31 ` Eric W. Biederman
2018-01-09 16:02   ` Willy Tarreau
2018-01-09 18:11     ` Zhi Wang
2018-01-09 21:07     ` Eric W. Biederman
2018-01-09 21:57       ` Willy Tarreau

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