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[46.139.12.213]) by smtp.gmail.com with ESMTPSA id g188sm6609478wmf.32.2018.11.22.23.38.01 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 22 Nov 2018 23:38:02 -0800 (PST) Date: Fri, 23 Nov 2018 08:37:59 +0100 From: Ingo Molnar To: Thomas Gleixner Cc: LKML , x86@kernel.org, Peter Zijlstra , Andy Lutomirski , Linus Torvalds , Jiri Kosina , Tom Lendacky , Josh Poimboeuf , Andrea Arcangeli , David Woodhouse , Andi Kleen , Dave Hansen , Casey Schaufler , Asit Mallick , Arjan van de Ven , Jon Masters , Waiman Long , Greg KH , Dave Stewart , Kees Cook Subject: Re: [patch 20/24] x86/speculation: Split out TIF update Message-ID: <20181123073759.GB12959@gmail.com> References: <20181121201430.559770965@linutronix.de> <20181121201724.227260385@linutronix.de> <20181122074322.GE41788@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Thomas Gleixner wrote: > On Thu, 22 Nov 2018, Ingo Molnar wrote: > > * Thomas Gleixner wrote: > > > > Had to read this twice, because the comment and the code are both correct > > but deal with the inverse case. This might have helped: > > > > /* > > * Immediately update the speculation MSRs on the current task, > > * but for non-current tasks delay setting the CPU mitigation > > * until it is scheduled next. > > */ > > if (tsk == current && update) > > speculation_ctrl_update_current(); > > > > But can the target task ever be non-current here? I don't think so: the > > two callers are prctl and seccomp, and both are passing in the current > > task pointer. > > See te other mail. Yes, seccomp passes non current task pointers. Will > update the comment. Ignore my previous mail :-) Thanks, Ingo