Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261969AbVCLQjW (ORCPT ); Sat, 12 Mar 2005 11:39:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261961AbVCLQhu (ORCPT ); Sat, 12 Mar 2005 11:37:50 -0500 Received: from fmr24.intel.com ([143.183.121.16]:64186 "EHLO scsfmr004.sc.intel.com") by vger.kernel.org with ESMTP id S261954AbVCLQhR (ORCPT ); Sat, 12 Mar 2005 11:37:17 -0500 Date: Sat, 12 Mar 2005 08:36:00 -0800 From: Venkatesh Pallipadi To: Zwane Mwaikambo Cc: George Anzinger , Andrew Morton , "J. Bruce Fields" , Lee Revell , Ingo Molnar , "linux-kernel@vger.kernel.org" Subject: Re: spin_lock error in arch/i386/kernel/time.c on APM resume Message-ID: <20050312083559.A23564@unix-os.sc.intel.com> References: <20050312131143.GA31038@fieldses.org> <4233111A.5070807@mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from zwane@arm.linux.org.uk on Sat, Mar 12, 2005 at 09:25:13AM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2711 Lines: 78 On Sat, Mar 12, 2005 at 09:25:13AM -0700, Zwane Mwaikambo wrote: > On Sat, 12 Mar 2005, George Anzinger wrote: > > > And more... That this occures implies we are attempting to update the cmos > > clock on resume seems wrong. One would presume that the time is wrong at this > > time and we are about to save that wrong time. Possibly the APM code should > > change time_status to STA_UNSYNC on the way into the sleep (or what ever it is > > called). Who should we ping with this? > > timer_resume, which appears to be the problem, wants to calculate amount > of time was spent suspended, also your unconditional irq enable in > get_cmos_time breaks the atomicity of device_power_up and would deadlock > in sections of code which call get_time_diff() with xtime_lock held. I > sent a patch subject "APM: fix interrupts enabled in device_power_up" > which should address this. > How about this patch? Also fixes one other use of rtc_lock in acpi/sleep/proc.c Thanks, Venki rtc_lock is held during timer interrupts. So, we should block interrupts while holding it. Signed-off-by: Venkatesh Pallipadi --- linux-2.6.10/arch/i386/kernel/time.c.org 2005-03-12 10:38:23.000000000 -0800 +++ linux-2.6.10/arch/i386/kernel/time.c 2005-03-12 10:40:26.000000000 -0800 @@ -305,15 +305,16 @@ irqreturn_t timer_interrupt(int irq, voi unsigned long get_cmos_time(void) { unsigned long retval; + unsigned long flags; - spin_lock(&rtc_lock); + spin_lock_irqsave(&rtc_lock, flags); if (efi_enabled) retval = efi_get_time(); else retval = mach_get_cmos_time(); - spin_unlock(&rtc_lock); + spin_unlock_restore(&rtc_lock, flags); return retval; } --- linux-2.6.10/drivers/acpi/sleep/proc.c.org 2005-03-12 10:50:40.000000000 -0800 +++ linux-2.6.10/drivers/acpi/sleep/proc.c 2005-03-12 10:53:08.000000000 -0800 @@ -84,10 +84,11 @@ static int acpi_system_alarm_seq_show(st u32 sec, min, hr; u32 day, mo, yr; unsigned char rtc_control = 0; + unsigned long flags; ACPI_FUNCTION_TRACE("acpi_system_alarm_seq_show"); - spin_lock(&rtc_lock); + spin_lock_irqsave(&rtc_lock, flags); sec = CMOS_READ(RTC_SECONDS_ALARM); min = CMOS_READ(RTC_MINUTES_ALARM); @@ -109,7 +110,7 @@ static int acpi_system_alarm_seq_show(st else yr = CMOS_READ(RTC_YEAR); - spin_unlock(&rtc_lock); + spin_unlock_restore(&rtc_lock, flags); if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BCD_TO_BIN(sec); - 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/