Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754485Ab0HPObq (ORCPT ); Mon, 16 Aug 2010 10:31:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10788 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753262Ab0HPObp (ORCPT ); Mon, 16 Aug 2010 10:31:45 -0400 Date: Mon, 16 Aug 2010 10:30:52 -0400 From: Don Zickus To: Sergey Senozhatsky Cc: Peter Zijlstra , Andrew Morton , Ingo Molnar , linux-kernel@vger.kernel.org, fweisbec@gmail.com Subject: Re: [PATCH] fix BUG using smp_processor_id() in touch_nmi_watchdog and touch_softlockup_watchdog Message-ID: <20100816143052.GV4879@redhat.com> References: <20100813102158.GA5434@swordfish.minsk.epam.com> <1281946970.1926.998.camel@laptop> <20100816133452.GS4879@redhat.com> <1281966418.1926.1421.camel@laptop> <20100816140829.GA5225@swordfish.minsk.epam.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100816140829.GA5225@swordfish.minsk.epam.com> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1773 Lines: 56 cc'ing Frederic On Mon, Aug 16, 2010 at 05:08:29PM +0300, Sergey Senozhatsky wrote: > Fix: acpi_os_stall calls touch_nmi_watchdog and touch_softlockup_watchdog > with preemption enabled causing 'BUG: using smp_processor_id() in preemptible > code'. > > Patch also removes double smp_processor_id call (smp_processor_id itself and in > __get_cpu_var) in __touch_watchdog. > > Signed-off-by: Sergey Senozhatsky Acked-by: Don Zickus > > --- > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index 613bc1f..8822f1e 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -116,13 +116,14 @@ static unsigned long get_sample_period(void) > static void __touch_watchdog(void) > { > int this_cpu = smp_processor_id(); > - > - __get_cpu_var(watchdog_touch_ts) = get_timestamp(this_cpu); > + per_cpu(watchdog_touch_ts, this_cpu) = get_timestamp(this_cpu); > } > > void touch_softlockup_watchdog(void) > { > - __get_cpu_var(watchdog_touch_ts) = 0; > + int this_cpu = get_cpu(); > + per_cpu(watchdog_touch_ts, this_cpu) = 0; > + put_cpu(); > } > EXPORT_SYMBOL(touch_softlockup_watchdog); > > @@ -142,7 +143,9 @@ void touch_all_softlockup_watchdogs(void) > #ifdef CONFIG_HARDLOCKUP_DETECTOR > void touch_nmi_watchdog(void) > { > - __get_cpu_var(watchdog_nmi_touch) = true; > + int this_cpu = get_cpu(); > + per_cpu(watchdog_nmi_touch, this_cpu) = true; > + put_cpu(); > touch_softlockup_watchdog(); > } > EXPORT_SYMBOL(touch_nmi_watchdog); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/