diff options
author | David P. Reed <dpreed@reed.com> | 2007-11-14 22:47:35 (GMT) |
---|---|---|
committer | Thomas Gleixner <tglx@apollo.(none)> | 2007-11-17 15:27:01 (GMT) |
commit | c399da0d97e06803e51085ec076b63a3168aad1b (patch) | |
tree | de37d0450254d8755f82db6ff6c392230698ca95 /arch | |
parent | fa6a1a554b50cbb7763f6907e6fef927ead480d9 (diff) | |
download | linux-c399da0d97e06803e51085ec076b63a3168aad1b.tar.xz |
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.
Signed-off-by: David P. Reed <dpreed@reed.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/kernel/time_64.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/arch/x86/kernel/time_64.c b/arch/x86/kernel/time_64.c index c821edc..4ad1f7a 100644 --- a/arch/x86/kernel/time_64.c +++ b/arch/x86/kernel/time_64.c @@ -82,18 +82,15 @@ 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); @@ -138,7 +135,7 @@ 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; } |