Re: [stable] 2.6.32.21 - uptime related crashes?

[Willy Tarreau <w@1wt.eu>]

On Sat, Apr 30, 2011 at 09:08:05AM -0700, Randy Dunlap wrote:
> On Sat, 30 Apr 2011 08:57:07 -0700 Greg KH wrote:
> 
> > On Sat, Apr 30, 2011 at 02:02:05PM +0200, Nikola Ciprich wrote:
> > > > There was a kernel parameter in the past that was used to make jiffies wrap
> > > > a few minutes after boot, maybe we should revive it to try to reproduce
> > > > without waiting 7 new months :-/
> > > hmm, I've googled this up, and it seems to have been 2.5.x patch, so it will
> > > certainly need some porting..
> > > I'll try to have a look on it tonight and report...
> > 
> > I don't think any patch is needed, I thought we did that by default now,
> > but I can't seem to find the code where it happens...
> > 
> > odd.
> 
> linux/jiffies.h:
> 
> /*
>  * Have the 32 bit jiffies value wrap 5 minutes after boot
>  * so jiffies wrap bugs show up earlier.
>  */
> #define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ))
> 
> 
> and kernel/timer.c:
> 
> u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;

Thanks Randy.

So that would mean that wrapping jiffies should be unrelated to the
reported panics. Let's wait for Hidetoshi-san's analysis then.

Regards,
Willy