From patchwork Mon Dec 23 06:03:51 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Kardashevskiy X-Patchwork-Id: 1214828 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=kvm-ppc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 47h81W6M54z9sR4 for ; Mon, 23 Dec 2019 17:03:59 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725855AbfLWGD6 (ORCPT ); Mon, 23 Dec 2019 01:03:58 -0500 Received: from 107-174-27-60-host.colocrossing.com ([107.174.27.60]:51832 "EHLO ozlabs.ru" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1725822AbfLWGD6 (ORCPT ); Mon, 23 Dec 2019 01:03:58 -0500 Received: from fstn1-p1.ozlabs.ibm.com (localhost [IPv6:::1]) by ozlabs.ru (Postfix) with ESMTP id 46322AE80026; Mon, 23 Dec 2019 01:02:44 -0500 (EST) From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , David Gibson , kvm-ppc@vger.kernel.org, Jan Kara , Michael Ellerman Subject: [PATCH kernel v3] powerpc/book3s64: Fix error handling in mm_iommu_do_alloc() Date: Mon, 23 Dec 2019 17:03:51 +1100 Message-Id: <20191223060351.26359-1-aik@ozlabs.ru> X-Mailer: git-send-email 2.17.1 Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org The last jump to free_exit in mm_iommu_do_alloc() happens after page pointers in struct mm_iommu_table_group_mem_t were already converted to physical addresses. Thus calling put_page() on these physical addresses will likely crash. This moves the loop which calculates the pageshift and converts page struct pointers to physical addresses later after the point when we cannot fail; thus eliminating the need to convert pointers back. Fixes: eb9d7a62c386 ("powerpc/mm_iommu: Fix potential deadlock") Reported-by: Jan Kara Signed-off-by: Alexey Kardashevskiy --- Changes: v3: * move pointers conversion after the last possible failure point --- arch/powerpc/mm/book3s64/iommu_api.c | 39 +++++++++++++++------------- 1 file changed, 21 insertions(+), 18 deletions(-) diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c index 56cc84520577..ef164851738b 100644 --- a/arch/powerpc/mm/book3s64/iommu_api.c +++ b/arch/powerpc/mm/book3s64/iommu_api.c @@ -121,24 +121,6 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, goto free_exit; } - pageshift = PAGE_SHIFT; - for (i = 0; i < entries; ++i) { - struct page *page = mem->hpages[i]; - - /* - * Allow to use larger than 64k IOMMU pages. Only do that - * if we are backed by hugetlb. - */ - if ((mem->pageshift > PAGE_SHIFT) && PageHuge(page)) - pageshift = page_shift(compound_head(page)); - mem->pageshift = min(mem->pageshift, pageshift); - /* - * We don't need struct page reference any more, switch - * to physical address. - */ - mem->hpas[i] = page_to_pfn(page) << PAGE_SHIFT; - } - good_exit: atomic64_set(&mem->mapped, 1); mem->used = 1; @@ -158,6 +140,27 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, } } + if (mem->dev_hpa == MM_IOMMU_TABLE_INVALID_HPA) { + /* + * Allow to use larger than 64k IOMMU pages. Only do that + * if we are backed by hugetlb. Skip device memory as it is not + * backed with page structs. + */ + pageshift = PAGE_SHIFT; + for (i = 0; i < entries; ++i) { + struct page *page = mem->hpages[i]; + + if ((mem->pageshift > PAGE_SHIFT) && PageHuge(page)) + pageshift = page_shift(compound_head(page)); + mem->pageshift = min(mem->pageshift, pageshift); + /* + * We don't need struct page reference any more, switch + * to physical address. + */ + mem->hpas[i] = page_to_pfn(page) << PAGE_SHIFT; + } + } + list_add_rcu(&mem->next, &mm->context.iommu_group_mem_list); mutex_unlock(&mem_list_mutex);