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=-9.0 required=3.0 tests=DATE_IN_PAST_06_12, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 4E3DDC4740C for ; Mon, 9 Sep 2019 22:16:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D56221A4A for ; Mon, 9 Sep 2019 22:16:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568067402; bh=M8QDHlclBiqqcG4kczDfCX8BbuxFzi0ECb4PydXMguo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vF2kIH821AnxJsqcKRJnJLu85GAuB3hSUyjcZTYiyt64xpOyk56u6mZZSiTKfcx5U WmjJ7AUL9KwmlYnfvzaPXM3QdzO4UvEPxcW7/LzMpbwxy6Z9v7Udyf40uuB2mA4ZbO pT6jl9LbAvujEhNRP4WvNZMeCoWBXmbnFl/1UFBM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406204AbfIIWQl (ORCPT ); Mon, 9 Sep 2019 18:16:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:45406 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406159AbfIIWQb (ORCPT ); Mon, 9 Sep 2019 18:16:31 -0400 Received: from sasha-vm.mshome.net (unknown [62.28.240.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7BB1F21D7D; Mon, 9 Sep 2019 22:16:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568067390; bh=M8QDHlclBiqqcG4kczDfCX8BbuxFzi0ECb4PydXMguo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YlRpmCRvLRl2w2pCVDdG2kYG08qeyMwt90luH2bphG7tYeOLkfljSQALCjWF65t+7 QPoQIXbJIjQRjIpv2OSeV1C/R9n4tEGk8PSJH6/Dn0QSvzBe/9ZvpofZEwRgUsrG7W LMfCSMKg5j3daoLwn+B4RnRMBXXEAjOfr5I6cH+4= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Joerg Roedel , Qian Cai , Sasha Levin , iommu@lists.linux-foundation.org Subject: [PATCH AUTOSEL 5.2 12/12] iommu/amd: Fix race in increase_address_space() Date: Mon, 9 Sep 2019 11:40:52 -0400 Message-Id: <20190909154052.30941-12-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190909154052.30941-1-sashal@kernel.org> References: <20190909154052.30941-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel [ Upstream commit 754265bcab78a9014f0f99cd35e0d610fcd7dfa7 ] After the conversion to lock-less dma-api call the increase_address_space() function can be called without any locking. Multiple CPUs could potentially race for increasing the address space, leading to invalid domain->mode settings and invalid page-tables. This has been happening in the wild under high IO load and memory pressure. Fix the race by locking this operation. The function is called infrequently so that this does not introduce a performance regression in the dma-api path again. Reported-by: Qian Cai Fixes: 256e4621c21a ('iommu/amd: Make use of the generic IOVA allocator') Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/amd_iommu.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index b265062edf6c8..3e687f18b203a 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -1425,18 +1425,21 @@ static void free_pagetable(struct protection_domain *domain) * another level increases the size of the address space by 9 bits to a size up * to 64 bits. */ -static bool increase_address_space(struct protection_domain *domain, +static void increase_address_space(struct protection_domain *domain, gfp_t gfp) { + unsigned long flags; u64 *pte; - if (domain->mode == PAGE_MODE_6_LEVEL) + spin_lock_irqsave(&domain->lock, flags); + + if (WARN_ON_ONCE(domain->mode == PAGE_MODE_6_LEVEL)) /* address space already 64 bit large */ - return false; + goto out; pte = (void *)get_zeroed_page(gfp); if (!pte) - return false; + goto out; *pte = PM_LEVEL_PDE(domain->mode, iommu_virt_to_phys(domain->pt_root)); @@ -1444,7 +1447,10 @@ static bool increase_address_space(struct protection_domain *domain, domain->mode += 1; domain->updated = true; - return true; +out: + spin_unlock_irqrestore(&domain->lock, flags); + + return; } static u64 *alloc_pte(struct protection_domain *domain, -- 2.20.1