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=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 E00BAC43603 for ; Wed, 4 Dec 2019 18:12:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B124420866 for ; Wed, 4 Dec 2019 18:12:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575483132; bh=SIJ+2AtMRSVhyjKuNp+YgzLxZeDID8jWrYk0fqKMcMQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=r8vJrzwCbIrF1ZHvWCy2NXh5am6RT8DZY6ZoPOegCeGFvacFOHqMTU91blskKnskh BMdjsqgqsNHOOz5AznkyxZ/D4afwUmWiusErjc9v4B/U3Kf7THhs4YlH2t+WDgdprb rpg6UHo9mNfQRhMOSGjOUmkEuHUHTschvoaYsRWk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731568AbfLDSML (ORCPT ); Wed, 4 Dec 2019 13:12:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:40668 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731558AbfLDSMI (ORCPT ); Wed, 4 Dec 2019 13:12:08 -0500 Received: from localhost (unknown [217.68.49.72]) (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 7287020675; Wed, 4 Dec 2019 18:12:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575483127; bh=SIJ+2AtMRSVhyjKuNp+YgzLxZeDID8jWrYk0fqKMcMQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XZb6AdgaLGtC8Ff7lWwHDN7dVdoWiS10ebVXRWoPARR3Qqa6xBRRERy+bigZgF6L8 r5FNdhEKSe5AUTNpwAlUn+Bi2iuYYxceefbn/V+FMBtodpJyIhDSeUmRrDm8Ly3F2x oqInIGRJjTajIGi0Gt/Jk0oK4yxBiu7xveNO91GI= 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 4.9 063/125] vfio/spapr_tce: Get rid of possible infinite loop Date: Wed, 4 Dec 2019 18:56:08 +0100 Message-Id: <20191204175322.803008587@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191204175308.377746305@linuxfoundation.org> References: <20191204175308.377746305@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 70c748a5fbcc2..a8e25f9409fa5 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -406,6 +406,7 @@ 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)) { @@ -428,13 +429,8 @@ 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