From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: broken suspend (sched related) [Was: 2.6.24-rc4-mm1] Date: Mon, 10 Dec 2007 10:10:52 +0100 Message-ID: <20071210091052.GA14487@elte.hu> References: <20071207151150.GB24254@elte.hu> <20071207175134.GA18916@elte.hu> <475A5188.6070809@gmail.com> <20071208083939.GD30997@elte.hu> <475A629C.7010408@gmail.com> <20071208152447.GA30270@elte.hu> <475B24F4.3090904@gmail.com> <20071209074647.GE22981@elte.hu> <20071210081952.GA7215@in.ibm.com> <475CFF01.2090502@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <475CFF01.2090502@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Jiri Slaby Cc: linux-kernel@vger.kernel.org, Linux-pm mailing list , Andrew Morton , Arjan van de Ven , Thomas Gleixner List-Id: linux-pm@vger.kernel.org > > softlockup: remove get_online_cpus() which doesn't help here. > > > > The get_online_cpus() protection seems to be bogus in > > kernel/softlockup.c as cpu cached in check_cpu can go offline once > > we do a put_online_cpus(). > > > > This can also cause deadlock during a cpu offline as follows: i'm wondering, what's the proper CPU-hotplug safe sequence here then? I'm picking a CPU number from cpu_online_map, and that CPU could go away while i'm still using it, right? What's saving us here? Ingo