diff options
| author | David P. Reed <dpreed@reed.com> | 2007-11-14 17:47:35 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-11-26 09:42:32 -0800 |
| commit | 653e60e2a9c16df6fccb3ae16f12d984cf83fb68 (patch) | |
| tree | 46cc0f6fe8140fad6ed9cbf98a861855677cbf65 /arch | |
| parent | 2d429c89279f78109db05d9b7db3348fc64b4ca5 (diff) | |
x86: fix freeze in x86_64 RTC update code in time_64.c
patch c399da0d97e06803e51085ec076b63a3168aad1b in mainline.
x86: fix freeze in x86_64 RTC update code in time_64.c
Fix hard freeze on x86_64 when the ntpd service calls
update_persistent_clock()
A repeatable but randomly timed freeze has been happening in Fedora 6
and 7 for the last year, whenever I run the ntpd service on my AMD64x2
HP Pavilion dv9000z laptop. This freeze is due to the use of
spin_lock(&rtc_lock) under the assumption (per a bad comment) that
set_rtc_mmss is called only with interrupts disabled. The call from
ntp.c to update_persistent_clock is made with interrupts enabled.
[ tglx@linutronix.de: ported to 2.6.23.stable ]
Signed-off-by: David P. Reed <dpreed@reed.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86_64/kernel/time.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c index 6d48a4e826d..4d0d1ac19a6 100644 --- a/arch/x86_64/kernel/time.c +++ b/arch/x86_64/kernel/time.c @@ -87,18 +87,15 @@ static int set_rtc_mmss(unsigned long nowtime) int retval = 0; int real_seconds, real_minutes, cmos_minutes; unsigned char control, freq_select; + unsigned long flags; /* - * IRQs are disabled when we're called from the timer interrupt, - * no need for spin_lock_irqsave() + * set_rtc_mmss is called when irqs are enabled, so disable irqs here */ - - spin_lock(&rtc_lock); - + spin_lock_irqsave(&rtc_lock, flags); /* * Tell the clock it's being set and stop it. */ - control = CMOS_READ(RTC_CONTROL); CMOS_WRITE(control | RTC_SET, RTC_CONTROL); @@ -143,7 +140,7 @@ static int set_rtc_mmss(unsigned long nowtime) CMOS_WRITE(control, RTC_CONTROL); CMOS_WRITE(freq_select, RTC_FREQ_SELECT); - spin_unlock(&rtc_lock); + spin_unlock_irqrestore(&rtc_lock, flags); return retval; } |