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=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 B7736C432C0 for ; Fri, 22 Nov 2019 06:24:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 82AE020674 for ; Fri, 22 Nov 2019 06:24:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574403854; bh=1lcF54AcbRONjDESSOA+6p0jhMgKCR+p52kcc7fQZc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EhchqSPbApNU1fun12TAwijUDA4b2o6UZEpsOt2Z+bUPqiBoBrfbQXB5841A1HK+n bqfVFfj7DpSUxUxNBGVdWqxh0hCHIJj1xFvBA0VEFPap3m7Lfp7BgdRu4RrHc6Wa/h JO2/Tci0QKvVux/EdqIi5qTwZOZZFhruzdyUY6vs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727996AbfKVGYN (ORCPT ); Fri, 22 Nov 2019 01:24:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:56644 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728157AbfKVFvb (ORCPT ); Fri, 22 Nov 2019 00:51:31 -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 46BF420731; Fri, 22 Nov 2019 05:51:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574401890; bh=1lcF54AcbRONjDESSOA+6p0jhMgKCR+p52kcc7fQZc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XKYhhS34Iyh7W7x47gFw4rfU1nPJXR2RZxIHk48GxGL7R9TSGxdQx0qIz7GbJdxEZ UCWVlcQAU1pAM/MFQysC0F8uxaJEVyNNtkSoBo9k/NYOiaBTUT4uzaHKceuwBaCDLj GPJVz9XkcV7Frdr/dxcwjFfkkVDMZrS7S7l5x5U0= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Alexey Kardashevskiy , David Gibson , Alex Williamson , Michael Ellerman , Sasha Levin , kvm@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 123/219] vfio/spapr_tce: Get rid of possible infinite loop Date: Fri, 22 Nov 2019 00:47:35 -0500 Message-Id: <20191122054911.1750-116-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191122054911.1750-1-sashal@kernel.org> References: <20191122054911.1750-1-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: Alexey Kardashevskiy [ Upstream commit 517ad4ae8aa93dccdb9a88c27257ecb421c9e848 ] As a part of cleanup, the SPAPR TCE IOMMU subdriver releases preregistered memory. If there is a bug in memory release, the loop in tce_iommu_release() becomes infinite; this actually happened to me. This makes the loop finite and prints a warning on every failure to make the code more bug prone. Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Acked-by: Alex Williamson Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- drivers/vfio/vfio_iommu_spapr_tce.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index 96721b154454f..ec53310f16136 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -371,6 +371,7 @@ static void tce_iommu_release(void *iommu_data) { struct tce_container *container = iommu_data; struct tce_iommu_group *tcegrp; + struct tce_iommu_prereg *tcemem, *tmtmp; long i; while (tce_groups_attached(container)) { @@ -393,13 +394,8 @@ static void tce_iommu_release(void *iommu_data) tce_iommu_free_table(container, tbl); } - while (!list_empty(&container->prereg_list)) { - struct tce_iommu_prereg *tcemem; - - tcemem = list_first_entry(&container->prereg_list, - struct tce_iommu_prereg, next); - WARN_ON_ONCE(tce_iommu_prereg_free(container, tcemem)); - } + list_for_each_entry_safe(tcemem, tmtmp, &container->prereg_list, next) + WARN_ON(tce_iommu_prereg_free(container, tcemem)); tce_iommu_disable(container); if (container->mm) -- 2.20.1