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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 B0B56C433E0 for ; Mon, 22 Feb 2021 23:18:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 230F464E4A for ; Mon, 22 Feb 2021 23:18:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 230F464E4A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4FA676B0005; Mon, 22 Feb 2021 18:18:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4AB186B006C; Mon, 22 Feb 2021 18:18:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3728D6B006E; Mon, 22 Feb 2021 18:18:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 230B36B0005 for ; Mon, 22 Feb 2021 18:18:02 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id DF9BA180AC15C for ; Mon, 22 Feb 2021 23:18:01 +0000 (UTC) X-FDA: 77847468762.01.994A12F Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf29.hostedemail.com (Postfix) with ESMTP id 56D30D7 for ; Mon, 22 Feb 2021 23:18:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614035880; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WGQQ0dkD9sIwTRkbZMYk3NFSu9qI5jVLuFsiEpZ0DKM=; b=FCvn5224X7M4OK6p2HdvNuLjz+i0sBupvQZhLnsKxrz9g/65gCU59oSCeVP7NfD7Jlq7/g +BJiWse9+/Twa2CQgYoGHZBKTWjP9NSuBQUyle797poTFH9gTnPio1RWZ39oUnm0JDYTgT ktXEsyr/11VuqBGAYqzatQ3oYUntqQc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-63-wGBFlDEyPtWmjAvq-hLuSQ-1; Mon, 22 Feb 2021 18:17:56 -0500 X-MC-Unique: wGBFlDEyPtWmjAvq-hLuSQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E1F1E100CCC0; Mon, 22 Feb 2021 23:17:54 +0000 (UTC) Received: from omen.home.shazbot.org (ovpn-112-255.phx2.redhat.com [10.3.112.255]) by smtp.corp.redhat.com (Postfix) with ESMTP id 46EEC5C1BD; Mon, 22 Feb 2021 23:17:54 +0000 (UTC) Date: Mon, 22 Feb 2021 16:17:53 -0700 From: Alex Williamson To: Dan Carpenter Cc: kbuild@lists.01.org, Steve Sistare , lkp@intel.com, kbuild-all@lists.01.org, Linux Memory Management List , Cornelia Huck Subject: Re: [kbuild] [linux-next:master 6931/12022] drivers/vfio/vfio_iommu_type1.c:1093 vfio_dma_do_unmap() warn: impossible condition '(size > (~0)) => (0-u32max > u32max)' Message-ID: <20210222161753.7acc4e92@omen.home.shazbot.org> In-Reply-To: <20210222155145.50e2d513@omen.home.shazbot.org> References: <20210222141043.GW2222@kadam> <20210222155145.50e2d513@omen.home.shazbot.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=alex.williamson@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 56D30D7 X-Stat-Signature: 61itfonur8gp4wihuemoj31hfdhmw6fc Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf29; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=216.205.24.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614035881-183116 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 22 Feb 2021 15:51:45 -0700 Alex Williamson wrote: > On Mon, 22 Feb 2021 17:10:43 +0300 > Dan Carpenter wrote: > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > head: 37dfbfbdca66834bc0f64ec9b35e09ac6c8898da > > commit: 0f53afa12baec8c00f5d1d6afb49325ada105253 [6931/12022] vfio/type1: unmap cleanup > > It's always the patches that claim no functional change... ;) > > > config: i386-randconfig-m021-20210222 (attached as .config) > > compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot > > Reported-by: Dan Carpenter > > > > New smatch warnings: > > drivers/vfio/vfio_iommu_type1.c:1093 vfio_dma_do_unmap() warn: impossible condition '(size > (~0)) => (0-u32max > u32max)' > > > > vim +1093 drivers/vfio/vfio_iommu_type1.c > > > > 73fa0d10d077d9 Alex Williamson 2012-07-31 1071 static int vfio_dma_do_unmap(struct vfio_iommu *iommu, > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1072 struct vfio_iommu_type1_dma_unmap *unmap, > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1073 struct vfio_bitmap *bitmap) > > 73fa0d10d077d9 Alex Williamson 2012-07-31 1074 { > > c086de818dd81c Kirti Wankhede 2016-11-17 1075 struct vfio_dma *dma, *dma_last = NULL; > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1076 size_t unmapped = 0, pgsize; > > 0f53afa12baec8 Steve Sistare 2021-01-29 1077 int ret = -EINVAL, retries = 0; > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1078 unsigned long pgshift; > > 0f53afa12baec8 Steve Sistare 2021-01-29 1079 dma_addr_t iova = unmap->iova; > > 0f53afa12baec8 Steve Sistare 2021-01-29 1080 unsigned long size = unmap->size; > > ^^^^^^^^^^^^^^^^^^ > > > > 73fa0d10d077d9 Alex Williamson 2012-07-31 1081 > > cade075f265b25 Kirti Wankhede 2020-05-29 1082 mutex_lock(&iommu->lock); > > cade075f265b25 Kirti Wankhede 2020-05-29 1083 > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1084 pgshift = __ffs(iommu->pgsize_bitmap); > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1085 pgsize = (size_t)1 << pgshift; > > cade075f265b25 Kirti Wankhede 2020-05-29 1086 > > 0f53afa12baec8 Steve Sistare 2021-01-29 1087 if (iova & (pgsize - 1)) > > cade075f265b25 Kirti Wankhede 2020-05-29 1088 goto unlock; > > cade075f265b25 Kirti Wankhede 2020-05-29 1089 > > 0f53afa12baec8 Steve Sistare 2021-01-29 1090 if (!size || size & (pgsize - 1)) > > cade075f265b25 Kirti Wankhede 2020-05-29 1091 goto unlock; > > 73fa0d10d077d9 Alex Williamson 2012-07-31 1092 > > 0f53afa12baec8 Steve Sistare 2021-01-29 @1093 if (iova + size - 1 < iova || size > SIZE_MAX) > > > > size is unsigned long and SIZE_MAX is ULONG_MAX so "size > SIZE_MAX" > > does not make sense. > > I think it made sense before the above commit, where unmap->size is a > __u64 and a user could provide a value that exceeds SIZE_MAX on ILP32. > Seems like the fix is probably to use a size_t for the local variable > and restore this test to compare (unmap->size > SIZE_MAX). Steve? Actually it seems like VFIO_DMA_UNMAP_FLAG_ALL doesn't work when PHYS_ADDR_MAX != SIZE_MAX (ex. x86 PAE - I think). I can't say I'm really interested in adding complexity to make it work in such a case either. Maybe we can just not expose it, ex: diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index ed03f3fcb07e..6b69a74b3db0 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -1207,7 +1207,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, int ret = -EINVAL, retries = 0; unsigned long pgshift; dma_addr_t iova = unmap->iova; - unsigned long size = unmap->size; + size_t size = unmap->size; bool unmap_all = unmap->flags & VFIO_DMA_UNMAP_FLAG_ALL; bool invalidate_vaddr = unmap->flags & VFIO_DMA_UNMAP_FLAG_VADDR; struct rb_node *n, *first_n; @@ -1228,7 +1228,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, goto unlock; } - if (iova + size - 1 < iova || size > SIZE_MAX) + if (iova + size - 1 < iova || unmap->size > SIZE_MAX) goto unlock; /* When dirty tracking is enabled, allow only min supported pgsize */ @@ -2657,9 +2657,10 @@ static int vfio_iommu_type1_check_extension(struct vfio_iommu *iommu, case VFIO_TYPE1_IOMMU: case VFIO_TYPE1v2_IOMMU: case VFIO_TYPE1_NESTING_IOMMU: - case VFIO_UNMAP_ALL: case VFIO_UPDATE_VADDR: return 1; + case VFIO_UNMAP_ALL: + return PHYS_ADDR_MAX == SIZE_MAX ? 1 : 0; case VFIO_DMA_CC_IOMMU: if (!iommu) return 0; @@ -2868,6 +2869,10 @@ static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu, VFIO_DMA_UNMAP_FLAG_VADDR))) return -EINVAL; + if ((PHYS_ADDR_MAX != SIZE_MAX) && + (unmap.flags & VFIO_DMA_UNMAP_FLAG_ALL)) + return -EINVAL; + if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) { unsigned long pgshift; > > Is the " - 1" intentional on the other overflow check? As in it's okay > > to wrap around to zero but not further than that? Sometimes this is > > intentional but it requires more subsystem expertise than I possess. > > Yes, since we're dealing with a start + length we need to account for > the -1 in the end value, otherwise the user could never unmap the last > page of the address space. Thanks for the report! > > Alex > > > cade075f265b25 Kirti Wankhede 2020-05-29 1094 goto unlock; > > 73fa0d10d077d9 Alex Williamson 2012-07-31 1095 > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1096 /* When dirty tracking is enabled, allow only min supported pgsize */ > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1097 if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) && > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1098 (!iommu->dirty_page_tracking || (bitmap->pgsize != pgsize))) { > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1099 goto unlock; > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1100 } > > 73fa0d10d077d9 Alex Williamson 2012-07-31 1101 > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1102 WARN_ON((pgsize - 1) & PAGE_MASK); > > 331e33d2960c82 Kirti Wankhede 2020-05-29 1103 again: > > 1ef3e2bc04223f Alex Williamson 2014-02-26 1104 /* > > > > --- > > 0-DAY CI Kernel Test Service, Intel Corporation > > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org >