From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31064 invoked by alias); 27 May 2009 17:45:38 -0000 Received: (qmail 31006 invoked by uid 22791); 27 May 2009 17:45:34 -0000 X-SWARE-Spam-Status: No, hits=-1.4 required=5.0 tests=AWL,BAYES_00,SPF_PASS X-Spam-Check-By: sourceware.org Received: from e8.ny.us.ibm.com (HELO e8.ny.us.ibm.com) (32.97.182.138) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 27 May 2009 17:45:29 +0000 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e8.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id n4RHZ7XP005194 for ; Wed, 27 May 2009 13:35:07 -0400 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n4RHjR2x244456 for ; Wed, 27 May 2009 13:45:27 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n4RHjQqH024094 for ; Wed, 27 May 2009 13:45:27 -0400 Received: from [9.65.0.6] (sig-9-65-0-6.mts.ibm.com [9.65.0.6]) by d01av03.pok.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id n4RHjNt1023916; Wed, 27 May 2009 13:45:24 -0400 Message-ID: <4A1D6DAA.9010608@us.ibm.com> Date: Wed, 27 May 2009 17:45:00 -0000 From: Darren Hart User-Agent: Thunderbird 2.0.0.21 (X11/20090318) MIME-Version: 1.0 To: Josh Stone CC: Kiran , systemtap@sources.redhat.com, sripathi@in.ibm.com, jkenisto@us.ibm.com, Paul McKenney Subject: Re: BUG: [preempt-rt] scheduling while atomic: stapio References: <1242812648.13247.12.camel@kiran-laptop> <4A145856.6080303@redhat.com> In-Reply-To: <4A145856.6080303@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2009-q2/txt/msg00715.txt.bz2 Josh Stone wrote: > On 05/20/2009 02:44 AM, Kiran wrote: >> BUG: scheduling while atomic: stapio/0x00000001/26142, CPU#3 >> [...] >> [] cpufreq_unregister_notifier+0x35/0x5c >> [] _stp_kill_time+0xb6/0xbd [stap_246f93f30a500769142af9987624737a_5072] >> [] probe_1391+0x3c/0xa8 [stap_246f93f30a500769142af9987624737a_5072] >> [] enter_end_probe+0x14a/0x1e3 [stap_246f93f30a500769142af9987624737a_5072] > > enter_end_probe will call preempt_disable, and apparently the call path > from cpufreq_unregister_notifier can sleep. Is this true only of the RT > kernel? The call into the __synchronize_sched() from synchronize_rcu() appears to be able to sleep regardless of -rt. It's possible -rt is more likely to make them sleep. -- Darren Hart IBM Linux Technology Center Real-Time Linux Team