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=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,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 BB273C433F4 for ; Mon, 24 Sep 2018 12:18:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81E7F208D9 for ; Mon, 24 Sep 2018 12:18:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 81E7F208D9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732590AbeIXSUU (ORCPT ); Mon, 24 Sep 2018 14:20:20 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56112 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730063AbeIXSUT (ORCPT ); Mon, 24 Sep 2018 14:20:19 -0400 Received: from localhost (ip-213-127-77-73.ip.prioritytelecom.net [213.127.77.73]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 11E791087; Mon, 24 Sep 2018 12:18:26 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pingfan Liu , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 4.14 067/173] drivers/base: stop new probing during shutdown Date: Mon, 24 Sep 2018 13:51:41 +0200 Message-Id: <20180924113120.955885442@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180924113114.334025954@linuxfoundation.org> References: <20180924113114.334025954@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pingfan Liu [ Upstream commit 3297c8fc65af5d40501ea7cddff1b195cae57e4e ] There is a race window in device_shutdown(), which may cause -1. parent device shut down before child or -2. no shutdown on a new probing device. For 1st, taking the following scenario: device_shutdown new plugin device list_del_init(parent_dev); spin_unlock(list_lock); device_add(child) probe child shutdown parent_dev --> now child is on the tail of devices_kset For 2nd, taking the following scenario: device_shutdown new plugin device device_add(dev) device_lock(dev); ... device_unlock(dev); probe dev --> now, the new occurred dev has no opportunity to shutdown To fix this race issue, just prevent the new probing request. With this logic, device_shutdown() is more similar to dpm_prepare(). Signed-off-by: Pingfan Liu Reviewed-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2783,6 +2783,9 @@ void device_shutdown(void) { struct device *dev, *parent; + wait_for_device_probe(); + device_block_probing(); + spin_lock(&devices_kset->list_lock); /* * Walk the devices list backward, shutting down each in turn.