[parisc-linux] travel backwards in time?

[Grant Grundler]

Randolph Chung wrote:
> Recently Grant and I have observed several hangs in do_gettimeofday on a
> c3k running 32 or 64-bit kernels (UP). 
> 
> The symptom we see is gettimeoffset returns a negative number which
> results in a huge (unsigned) usec offset in do_gettimeofday, which ends
> up spinning in a while loop.
...
> The last_tick adjustment looks a bit odd. Looking at ia64, it looks more
> like this:
> 
>         last_tick -= clocktick * (jiffies - wall_jiffies + 1);

For the record, this fix was committed in one of the 2.4.14-pa5
http://lists.parisc-linux.org/pipermail/parisc-linux-cvs/2001-November/030021.html

I'm still not 100% certain all our time keeping code is correct.
But I'm comfortable this patch fixes the problem we saw and
does not introduce any new ones.

grant