xen/swiotlb: fix condition for calling xen_destroy_contiguous_region()
Juergen Gross authored
commit 50f6393f

 upstream.

The condition in xen_swiotlb_free_coherent() for deciding whether to
call xen_destroy_contiguous_region() is wrong: in case the region to
be freed is not contiguous calling xen_destroy_contiguous_region() is
the wrong thing to do: it would result in inconsistent mappings of
multiple PFNs to the same MFN. This will lead to various strange
crashes or data corruption.

Instead of calling xen_destroy_contiguous_region() in that case a
warning should be issued as that situation should never occur.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: default avatarJan Beulich <jbeulich@suse.com>
Acked-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
04fdca1f
Linux kernel
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