From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32472C3F2D1 for ; Wed, 4 Mar 2020 12:37:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1424820848 for ; Wed, 4 Mar 2020 12:37:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388045AbgCDMg7 (ORCPT ); Wed, 4 Mar 2020 07:36:59 -0500 Received: from foss.arm.com ([217.140.110.172]:33774 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388005AbgCDMg6 (ORCPT ); Wed, 4 Mar 2020 07:36:58 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E353731B; Wed, 4 Mar 2020 04:36:57 -0800 (PST) Received: from [10.1.196.37] (e121345-lin.cambridge.arm.com [10.1.196.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F0CDB3F6C4; Wed, 4 Mar 2020 04:36:56 -0800 (PST) Subject: Re: [PATCH v2] iommu/dma: Fix MSI reservation allocation To: Marc Zyngier , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Eric Auger , Joerg Roedel , Will Deacon , stable@vger.kernel.org References: <20200304111117.3540-1-maz@kernel.org> From: Robin Murphy Message-ID: <35a91284-619e-398a-decc-2e3879702335@arm.com> Date: Wed, 4 Mar 2020 12:36:54 +0000 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200304111117.3540-1-maz@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/03/2020 11:11 am, Marc Zyngier wrote: > The way cookie_init_hw_msi_region() allocates the iommu_dma_msi_page > structures doesn't match the way iommu_put_dma_cookie() frees them. > > The former performs a single allocation of all the required structures, > while the latter tries to free them one at a time. It doesn't quite > work for the main use case (the GICv3 ITS where the range is 64kB) > when the base granule size is 4kB. > > This leads to a nice slab corruption on teardown, which is easily > observable by simply creating a VF on a SRIOV-capable device, and > tearing it down immediately (no need to even make use of it). > Fortunately, this only affects systems where the ITS isn't translated > by the SMMU, which are both rare and non-standard. > > Fix it by allocating iommu_dma_msi_page structures one at a time. Reviewed-by: Robin Murphy > Fixes: 7c1b058c8b5a3 ("iommu/dma: Handle IOMMU API reserved regions") > Signed-off-by: Marc Zyngier > Reviewed-by: Eric Auger > Cc: Robin Murphy > Cc: Joerg Roedel > Cc: Will Deacon > Cc: stable@vger.kernel.org > --- > * From v1: > - Got rid of the superfluous error handling (Robin) > - Clarified that it only affects a very small set of systems > - Added Eric's RB (which I assume still stands) > > drivers/iommu/dma-iommu.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index a2e96a5fd9a7..ba128d1cdaee 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -177,15 +177,15 @@ static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie, > start -= iova_offset(iovad, start); > num_pages = iova_align(iovad, end - start) >> iova_shift(iovad); > > - msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL); > - if (!msi_page) > - return -ENOMEM; > - > for (i = 0; i < num_pages; i++) { > - msi_page[i].phys = start; > - msi_page[i].iova = start; > - INIT_LIST_HEAD(&msi_page[i].list); > - list_add(&msi_page[i].list, &cookie->msi_page_list); > + msi_page = kmalloc(sizeof(*msi_page), GFP_KERNEL); > + if (!msi_page) > + return -ENOMEM; > + > + msi_page->phys = start; > + msi_page->iova = start; > + INIT_LIST_HEAD(&msi_page->list); > + list_add(&msi_page->list, &cookie->msi_page_list); > start += iovad->granule; > } > >