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=-8.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLACK,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 CFE3EC432C3 for ; Tue, 3 Dec 2019 23:02:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A020420674 for ; Tue, 3 Dec 2019 23:02:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575414149; bh=1lcF54AcbRONjDESSOA+6p0jhMgKCR+p52kcc7fQZc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=g3R6159u2qMejSWZuqJ29Oi9mIkIQAFkf8ypEcOogew9yJH7l9SLFS4BFSQHZGRDf 2vynx8MKawYyYKAAY8Mlk4n2gHXevQHPvRCD1bB3qIVK9a2yIjcZBa4CbWqGZadVGk fbeo2/tGf0/RaKsDz2TBCVBLB5nlbbr7/J3ONlHU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729652AbfLCWym (ORCPT ); Tue, 3 Dec 2019 17:54:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:48474 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728397AbfLCWyd (ORCPT ); Tue, 3 Dec 2019 17:54:33 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9983F21582; Tue, 3 Dec 2019 22:54:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575413673; bh=1lcF54AcbRONjDESSOA+6p0jhMgKCR+p52kcc7fQZc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DWKczIaIWPXe43FkoUik1sFQuOMTa4BbTcCKh8YfcMjbUgDiumiH9mD2dpJ8YB4fN yajI6GL1AJpiLsqonhuJOWYvFu5y4+9FeCa1HFBztUidKzeZKSEXZsGkrrlSC7LCVg DveCAl9ckQvKKh14z15pXtG60vT7G7qVn3FjVMcw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexey Kardashevskiy , David Gibson , Alex Williamson , Michael Ellerman , Sasha Levin Subject: [PATCH 4.19 169/321] vfio/spapr_tce: Get rid of possible infinite loop Date: Tue, 3 Dec 2019 23:33:55 +0100 Message-Id: <20191203223435.927454925@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191203223427.103571230@linuxfoundation.org> References: <20191203223427.103571230@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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