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Commit b6497b38 authored by Ian Campbell's avatar Ian Campbell Committed by Stefano Stabellini
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xen: privcmd: do not return pages which we have failed to unmap 



This failure represents a hypervisor issue, but if it does occur then nothing
good can come of returning pages which still refer to a foreign owned page
into the general allocation pool.

Instead we are forced to leak them. Log that we have done so.

The potential for failure only exists for autotranslated guest (e.g. ARM and
x86 PVH).

Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent c94cae53

drivers/xen/privcmd.c

+7 −2
Original line number Diff line number Diff line
@@ -533,12 +533,17 @@ static void privcmd_close(struct vm_area_struct *vma) 
{

	struct page **pages = vma->vm_private_data;

	int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;

	int rc;



	if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)

		return;



	xen_unmap_domain_mfn_range(vma, numpgs, pages);

	rc = xen_unmap_domain_mfn_range(vma, numpgs, pages);

	if (rc == 0)

		free_xenballooned_pages(numpgs, pages);

	else

		pr_crit("unable to unmap MFN range: leaking %d pages. rc=%d\n",

			numpgs, rc);

	kfree(pages);

}