Re: 2.4.14 + Bug in swap_out.

From: Rik van Riel (riel@conectiva.com.br)
Date: Wed Nov 21 2001 - 07:13:52 EST


On 20 Nov 2001, Eric W. Biederman wrote:

> /* Make sure the mm doesn't disappear when we drop the lock.. */
> atomic_inc(&mm->mm_users);
> spin_unlock(&mmlist_lock);
>
> nr_pages = swap_out_mm(mm, nr_pages, &counter, classzone);
>
> mmput(mm);
>
>
> And looking in fork.c mmput under with right circumstances becomes.
> kmem_cache_free(mm_cachep, (mm)))
>
> So it appears that there is nothing that keeps the mm_struct that
> swap_mm points to as being valid.

The atomic_inc(&mm->mm_users) above should make sure this
mm_struct stays valid.

regards,

Rik

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