Software Emulation Exception...

[Marcus Sundberg]

Dan Malek <dan at netx4.com> writes:

> Marcus Sundberg wrote:
>
> > .... It has a 100% chance of crashing without the patch, and a 0%
> > chance of crashing with it.
>
> I agree the patch is necessary to fix a problem managing dirty
> pages......
>
> > All you have to do to experience the problem is allocate memory
> > until the RAM gets low
>
> ....but this wasn't the test....

I haven't seen any posts about "the test", but I doubt you can find
a better test for the dirty page bug.

> > .... If you are running a dynamicly linked glibc2
> > app what is most likely to happen is that the (dirty) jump table
> > is thrown out by the broken MM code.
>
> If, if, if......Is this really what is happening?

For me it is - I've watched the pte_val of a dirty page containg
the jump table change to zero (kernel throwing the page out), and
seen the crash when the page is being paged back in from disk.

Obviously I can't be sure about other peoples problems as I haven't
seen them happen, but if both the symptoms and the fix are identical
there is a good chance that the problem is the same as well.

>  I am concerned about proving a real problem and fixing it.
> If you aren't, that's OK.  I have other things to do.

A (serious) real problem has been found, and the fix is available.

//Marcus
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