linux-kernel - Re: [patch V2 09/17] x86/entry: Remove _TIF_NOHZ from _TIF_WORK_SYSCALL

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200106041124.GA26097@lenoir>
Date:   Mon, 6 Jan 2020 05:11:25 +0100
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Will Deacon <will@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-arch@...r.kernel.org, Mike Rapoport <rppt@...ux.ibm.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Miroslav Benes <mbenes@...e.cz>
Subject: Re: [patch V2 09/17] x86/entry: Remove _TIF_NOHZ from
 _TIF_WORK_SYSCALL_ENTRY

On Wed, Oct 23, 2019 at 02:27:14PM +0200, Thomas Gleixner wrote:
> From: Thomas Gleixner <tglx@...utronix.de>
> 
> Evaluating _TIF_NOHZ to decide whether to use the slow syscall entry path
> is not only pointless, it's actually counterproductive:
> 
>  1) Context tracking code is invoked unconditionally before that flag is
>     evaluated.
> 
>  2) If the flag is set the slow path is invoked for nothing due to #1
> 
> Remove it.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

I'm borrowing this patch for a series of mine. But if you apply
it in the meantime, that would be even better :-)

Thanks!