If we fail to allocate an indirect buffer (ib) when updating the ptes, return an error instead of trying to use the ib. Avoids a null pointer dereference. Bug: https://bugzilla.kernel.org/show_bug.cgi?id=58621 Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org