Re: Oops in __free_pages_ok (pre7-1) (Long) (backtrace)

[Rajagopal Ananthanarayanan <ananth@sgi.com>]

Linus Torvalds wrote:
> 
> On Wed, 3 May 2000, Kanoj Sarcar wrote:
> >
> > At no point between the time try_to_swap_out() is running, will is_page_shared()
> > wrongly indicate the page is _not shared_, when it is really shared (as you
> > say, it is pessimistic).
> 

> 
> _Something_ obviously triggers on the x86, though.

IMHO, that's the right attitude. I really like the idea of
having the page locked if its state is being fiddled with.
I know, we don't fully understand the problem, in the sense
that no one has been able to construct a sample execution
which will hit the bug. But so what? Since the bug is elusive,
even if one comes up with a scenario, no saying that _that_
is what happened during the particular manifestation.

	[ ... ]

> 
> We fixed one such bug in NFS. Maybe there are more lurking? How much
> memory do the machines have that have problems?
> 

I don't use NFS on my test systems. So, that couldn't have
been a problem. I had about 64MB of memory in the system.

BTW, I've been running the test (some tar & diff) for
several hours now on the same system. The system is staying up fine.

regards,

ananth.
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