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SubjectRe: [PATCH 1/3] revoke: misc fixes
Pekka J Enberg wrote:
> > /*
> > - * Not holding ->mmap_sem here.
> > + * Not holding ->mmap_sem here but we must watch out for page
> > + * faults and after the shared mappings have been taken down
> > + * and sys_mmap() trying to remap the revoked range.
> > */
> > vma->vm_flags |= VM_REVOKED;
> > smp_mb();
> > @@ -455,7 +457,7 @@ int err = 0;

On Fri, 16 Mar 2007, Nick Piggin wrote:
> You're still modifying vm_flags without down_write mmap_sem, so this will
> corrupt vm_flags.

Uhm, you're right, two concurrent writes and we can lose some bits so a
barrier doesn't work. Too bad as we're under mapping->i_mmap_lock here and
thus cannot take ->mmap_sep...
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