On Fri, Nov 16, 2007 at 11:26:17AM +0800, Li Zefan wrote:
> Aristeu Rozanski wrote:
> > Hello Dan,
> >> Patch is valid only for 2.6.23.x, guessing from the recent arch/ changes
> >> in 2.6.24-rc.
> >>
> >> set_rtc_mmss() was used to be called from interrupt context in 2.6.22,
> >> however in 2.6.23, it is called from a timer context, where interrupts
> >> are enabled. This patch ensures that rtc_interrupt() won't dead-lock
> >> with set_rtc_mmss().
> >
> >> diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
> >> index 6241b50..8414236 100644
> >> --- a/arch/x86_64/kernel/time.c
> >> +++ b/arch/x86_64/kernel/time.c
> >> @@ -87,13 +87,14 @@ 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()
> >> */
> >>
> >> - spin_lock(&rtc_lock);
> >> + spin_lock_irqsave(&rtc_lock, flags);
> > I think it's a good idea to update or just remove the comment above.
> >
>
> David P. Reed has sent a patch to fix this bug before you.
>
> http://lkml.org/lkml/2007/11/14/435
Yes, missed by a day. Although that patch was aimed for 2.6.24-rc,
I am currently more concerned about the 2.6.23.x tree.
Greg, can this be added to 2.6.23-stable?
Signed-off-by: Dan Aloni <[EMAIL PROTECTED]>
---
commit 26c05aa66d10e95de63d95a348023ada4827ceed
tree 7c12f2b35fcba31c9f62ba278b9d232406f80e83
parent ad1765c56c2178a09e87d123548a35f221e1fc05
author Dan Aloni <[EMAIL PROTECTED]> Sat, 17 Nov 2007 10:31:01 +0200
committer Dan Aloni <[EMAIL PROTECTED]> Sat, 17 Nov 2007 10:31:01 +0200
arch/x86_64/kernel/time.c | 10 +++-------
1 files changed, 3 insertions(+), 7 deletions(-)
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 6d48a4e..fde5796 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -87,13 +87,9 @@ 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()
- */
-
- spin_lock(&rtc_lock);
+ spin_lock_irqsave(&rtc_lock, flags);
/*
* Tell the clock it's being set and stop it.
@@ -143,7 +139,7 @@ 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;
}
--
Dan Aloni
XIV LTD, http://www.xivstorage.com
da-x (at) monatomic.org, dan (at) xiv.co.il
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