From patchwork Tue Aug 24 07:20:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Long Li X-Patchwork-Id: 12454071 X-Patchwork-Delegate: lorenzo.pieralisi@arm.com 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 D3155C4338F for ; Tue, 24 Aug 2021 07:20:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8681613B1 for ; Tue, 24 Aug 2021 07:20:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233436AbhHXHVI (ORCPT ); Tue, 24 Aug 2021 03:21:08 -0400 Received: from linux.microsoft.com ([13.77.154.182]:54612 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232173AbhHXHVH (ORCPT ); Tue, 24 Aug 2021 03:21:07 -0400 Received: by linux.microsoft.com (Postfix, from userid 1004) id 1BE3320B7192; Tue, 24 Aug 2021 00:20:24 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1BE3320B7192 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxonhyperv.com; s=default; t=1629789624; bh=pT9MfMBwFEzM8B1XTfJ8fkYHPKmhI6ubzUcWHq4gd20=; h=From:To:Cc:Subject:Date:From; b=lLWFly0aKAauojK7Rlr2GcDxHv76/4KGNj99MTYveFGZBo5d+JCmMGofQaXqrnjVA 7qxnwLDf6wZr3065KuPO1VKK4EJ/dLRzB8QpdqqDeOz5sVeDFnDiBuMmh1iEYPvaTV zWHAFTJs0q0UJr/aNG4sFBqksr+26PNektX9c1gY= From: longli@linuxonhyperv.com To: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org Cc: Long Li , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , Dexuan Cui , Lorenzo Pieralisi , Rob Herring , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , Bjorn Helgaas , Michael Kelley , Dan Carpenter Subject: [PATCH] PCI: hv: Fix a bug on removing child devices on the bus Date: Tue, 24 Aug 2021 00:20:20 -0700 Message-Id: <1629789620-11049-1-git-send-email-longli@linuxonhyperv.com> X-Mailer: git-send-email 1.8.3.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Long Li In hv_pci_bus_exit, the code is holding a spinlock while calling pci_destroy_slot(), which takes a mutex. This is not safe for spinlock. Fix this by moving the children to be deleted to a list on the stack, and removing them after spinlock is released. Fixes: 94d22763207a ("PCI: hv: Fix a race condition when removing the device") Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Wei Liu Cc: Dexuan Cui Cc: Lorenzo Pieralisi Cc: Rob Herring Cc: "Krzysztof Wilczyński" Cc: Bjorn Helgaas Cc: Michael Kelley Cc: Dan Carpenter Reported-by: Dan Carpenter Signed-off-by: Long Li --- drivers/pci/controller/pci-hyperv.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index a53bd8728d0d..d4f3cce18957 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -3220,6 +3220,7 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) struct hv_pci_dev *hpdev, *tmp; unsigned long flags; int ret; + struct list_head removed; /* * After the host sends the RESCIND_CHANNEL message, it doesn't @@ -3229,9 +3230,18 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) return 0; if (!keep_devs) { - /* Delete any children which might still exist. */ + INIT_LIST_HEAD(&removed); + + /* Move all present children to the list on stack */ spin_lock_irqsave(&hbus->device_list_lock, flags); - list_for_each_entry_safe(hpdev, tmp, &hbus->children, list_entry) { + list_for_each_entry_safe(hpdev, tmp, &hbus->children, list_entry) + list_move_tail(&hpdev->list_entry, &removed); + spin_unlock_irqrestore(&hbus->device_list_lock, flags); + + /* Remove all children in the list */ + while (!list_empty(&removed)) { + hpdev = list_first_entry(&removed, struct hv_pci_dev, + list_entry); list_del(&hpdev->list_entry); if (hpdev->pci_slot) pci_destroy_slot(hpdev->pci_slot); @@ -3239,7 +3249,6 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) put_pcichild(hpdev); put_pcichild(hpdev); } - spin_unlock_irqrestore(&hbus->device_list_lock, flags); } ret = hv_send_resources_released(hdev);