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=-10.1 required=3.0 tests=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=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 DED00C17440 for ; Sun, 10 Nov 2019 03:02:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB56021848 for ; Sun, 10 Nov 2019 03:02:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573354979; bh=ekjUL9iEKKF0msi9brH469zdJuKPgU6PU/D6LgKa3SA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BJK2Fxyo/5Ba2eXmk86xFAjGvhmLJrMBR8kflmMCb+QlhjSG8p2Umsat2jr1b2Yut b6Vvg1k4oX2lGqQFI1r9+HAeYlZOI53qi/SmYomKMMEHYupaEjSNNUWh++T2N9ggPW 9G+IbxHVqD8mEKFbCfeBxrZ6CHGBDf+YuK0aamKw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729360AbfKJCsz (ORCPT ); Sat, 9 Nov 2019 21:48:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:56770 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729327AbfKJCsw (ORCPT ); Sat, 9 Nov 2019 21:48:52 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 6161422573; Sun, 10 Nov 2019 02:48:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573354132; bh=ekjUL9iEKKF0msi9brH469zdJuKPgU6PU/D6LgKa3SA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iluuvFwOyTcb2MUUd31672baK6BvMk2EzqFbSk4Y6gYJtBFzW/BxBItspwcEM4KJ7 qiqBXiCxQPYUDJGPVzvBuLwqeVhIY/pTeVUhV0+PauSzvpzFIo7vLpGwYRE9J6Eg7K MrmKgLvTEOr9VUIMzrOVccr3O2rHeWCMDNdT7Xwg= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Breno Leitao , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 4.9 04/66] powerpc/iommu: Avoid derefence before pointer check Date: Sat, 9 Nov 2019 21:47:43 -0500 Message-Id: <20191110024846.32598-4-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191110024846.32598-1-sashal@kernel.org> References: <20191110024846.32598-1-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: Breno Leitao [ Upstream commit 984ecdd68de0fa1f63ce205d6c19ef5a7bc67b40 ] The tbl pointer is being derefenced by IOMMU_PAGE_SIZE prior the check if it is not NULL. Just moving the dereference code to after the check, where there will be guarantee that 'tbl' will not be NULL. Signed-off-by: Breno Leitao Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- arch/powerpc/kernel/iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index 5f202a566ec5f..9bfdd2510fd5e 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -765,9 +765,9 @@ dma_addr_t iommu_map_page(struct device *dev, struct iommu_table *tbl, vaddr = page_address(page) + offset; uaddr = (unsigned long)vaddr; - npages = iommu_num_pages(uaddr, size, IOMMU_PAGE_SIZE(tbl)); if (tbl) { + npages = iommu_num_pages(uaddr, size, IOMMU_PAGE_SIZE(tbl)); align = 0; if (tbl->it_page_shift < PAGE_SHIFT && size >= PAGE_SIZE && ((unsigned long)vaddr & ~PAGE_MASK) == 0) -- 2.20.1