linux-kernel - Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable for synchronization

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: <20151208065905.GA3294@ubuntu>
Date:	Tue, 8 Dec 2015 12:29:05 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	linux-pm@...r.kernel.org, linaro-kernel@...ts.linaro.org,
	ashwin.chaugule@...aro.org,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH][experimantal] cpufreq: governor: Use an atomic variable
 for synchronization

On 08-12-15, 01:39, Rafael J. Wysocki wrote:
> @@ -269,9 +259,6 @@ static void dbs_timer_handler(unsigned l
>  {
>  	struct cpu_dbs_info *cdbs = (struct cpu_dbs_info *)data;
>  	struct cpu_common_dbs_info *shared = cdbs->shared;
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&shared->timer_lock, flags);
>  
>  	/*
>  	 * Timer handler isn't allowed to queue work at the moment, because:
> @@ -279,12 +266,10 @@ static void dbs_timer_handler(unsigned l
>  	 * - We are stopping the governor
>  	 * - Or we are updating the sampling rate of ondemand governor
>  	 */
> -	if (!shared->skip_work) {
> -		shared->skip_work++;
> +	if (atomic_inc_return(&shared->skip_work) > 1)
> +		atomic_dec(&shared->skip_work);
> +	else
>  		queue_work(system_wq, &shared->work);
> -	}

As explained in the other email, this is wrong..

-- 
viresh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/