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 9C75AC432C0 for ; Fri, 22 Nov 2019 06:06:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 650652070A for ; Fri, 22 Nov 2019 06:06:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574402772; bh=SIJ+2AtMRSVhyjKuNp+YgzLxZeDID8jWrYk0fqKMcMQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fCNG5yzfN9dY7a4gEkbKxlnk5K+JlAdxhA5EmrulSvUc3VK6oRYRZqdkUNGOsNNUl eihJ8s7iQmOlj/Cj0hChAxHMn/NMFwHy2uq3EGZrmRNO8ur/dbC0wAbsr/AzyHuJwo 74LI9XsADOk4Bh4BSMV71MEGbx7Yp3vqVv8CkhRQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728807AbfKVGGL (ORCPT ); Fri, 22 Nov 2019 01:06:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:41000 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729710AbfKVGCY (ORCPT ); Fri, 22 Nov 2019 01:02:24 -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 1029820714; Fri, 22 Nov 2019 06:02:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574402543; bh=SIJ+2AtMRSVhyjKuNp+YgzLxZeDID8jWrYk0fqKMcMQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rfHjXdBjPuM1JUh9N6/bXmC85/t0yq1zAhVC+iAAhv8xOO4I41SPbhtoeSoQKpaF9 bzd0o99TDUaNsp8VnNquRgPR26tgeZod2FjVbyBfutNNotVfckGEl9EckB9LM5djRn X2YO6cw4KrgcK3EMGpNVetBcn7yOnwBXxi/rvKEk= 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 4.9 50/91] vfio/spapr_tce: Get rid of possible infinite loop Date: Fri, 22 Nov 2019 01:00:48 -0500 Message-Id: <20191122060129.4239-49-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191122060129.4239-1-sashal@kernel.org> References: <20191122060129.4239-1-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 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