linux-kernel - Re: [PATCH v6 1/2] cpufreq: split the cpufreq_driver

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]

Date:	Wed, 03 Apr 2013 00:57:50 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	Nathan Zimmer <nzimmer@....com>, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 1/2] cpufreq: split the cpufreq_driver_lock and use the rcu

On Tuesday, April 02, 2013 08:29:12 PM Viresh Kumar wrote:
> On 2 April 2013 20:25, Nathan Zimmer <nzimmer@....com> wrote:
> > The lock is unneeded if we expect register and unregister driver to not be
> > called from muliple threads at once.  I didn't make that assumption.
> 
> Hmm.. But doesn't rcu part take care of that too?? Two writers
> updating stuff simultaneously?

RCU doesn't cover that in general.  Additional locking is needed to provide
synchronization between writers.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
--
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/