From: Ian Campbell Date: Fri, 6 Dec 2013 17:55:56 +0000 (+0000) Subject: xen: privcmd: do not return pages which we have failed to unmap X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b6497b383f65dd1bc60ea1f5d70e157a268fbd15;p=linux-beck.git 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: Ian Campbell Signed-off-by: Stefano Stabellini Reviewed-by: David Vrabel --- diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index 8e74590fa1bb..569a13b9e856 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -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); - free_xenballooned_pages(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); }