linux-kernel - Re: [patch 1/3] tick: Remove pointless cpu valid check in hotplug code

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: <20201207115953.GR3021@hirez.programming.kicks-ass.net>
Date:   Mon, 7 Dec 2020 12:59:53 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Marco Elver <elver@...gle.com>,
        kasan-dev <kasan-dev@...glegroups.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Will Deacon <will@...nel.org>,
        Naresh Kamboju <naresh.kamboju@...aro.org>
Subject: Re: [patch 1/3] tick: Remove pointless cpu valid check in hotplug
 code

On Sun, Dec 06, 2020 at 10:12:54PM +0100, Thomas Gleixner wrote:

>  void tick_handover_do_timer(void)
>  {
> +	if (tick_do_timer_cpu == smp_processor_id())
> +		tick_do_timer_cpu = cpumask_first(cpu_online_mask);

For the paranoid amongst us, would it make sense to add something like:

	/*
	 * There must always be at least one online CPU.
	 */
	WARN_ON_ONCE(tick_do_timer_cpu >= nr_cpu_ids);

>  }