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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 8C0C5C433E8 for ; Tue, 14 Jul 2020 18:46:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6BFB922B40 for ; Tue, 14 Jul 2020 18:46:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752414; bh=bQdhkyleKNrB/eAmk3MoXZ4uuEJHYABQVPYga/A9WNQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=foHcSXrWAmhHcfA6h424CjaKQPEVE7nS7qp2f88pegScBhiSsEW1nsZW3T37xj/HO tEDsHTkSmh2+WCjB4GP/bgrumqN5s9v4TFs1LgYa2FaPjYyObKJ3FCvQGyGdO/RzCj aaU2ZJmnIsktbKoeCm0hKLIfj11bkmxHGRr4k1GY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729616AbgGNSqx (ORCPT ); Tue, 14 Jul 2020 14:46:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:41668 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729598AbgGNSqt (ORCPT ); Tue, 14 Jul 2020 14:46:49 -0400 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 E841F222E9; Tue, 14 Jul 2020 18:46:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752408; bh=bQdhkyleKNrB/eAmk3MoXZ4uuEJHYABQVPYga/A9WNQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uR2xoc2JjmhVWPNyqxVimfN8wpbD6q+xbBAOYMvsj/yNiGyNR7QZ0M1HjCN5okgW9 KkZG1huw+2gKh0ctmsVFiXGCaCt7YuaOeXgbF55rgniTLBbLN+7jOHi39yvSmG+jfd dEP/Z8IiqTKLBrMwxnZKnLCgXwADC9sWqr36hlvs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhenzhong Duan , Mark Brown , Sasha Levin Subject: [PATCH 4.19 10/58] spi: spidev: fix a race between spidev_release and spidev_remove Date: Tue, 14 Jul 2020 20:43:43 +0200 Message-Id: <20200714184056.651102376@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714184056.149119318@linuxfoundation.org> References: <20200714184056.149119318@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: Zhenzhong Duan [ Upstream commit abd42781c3d2155868821f1b947ae45bbc33330d ] Imagine below scene, spidev is referenced after it's freed. spidev_release() spidev_remove() ... spin_lock_irq(&spidev->spi_lock); spidev->spi = NULL; spin_unlock_irq(&spidev->spi_lock); mutex_lock(&device_list_lock); dofree = (spidev->spi == NULL); if (dofree) kfree(spidev); mutex_unlock(&device_list_lock); mutex_lock(&device_list_lock); list_del(&spidev->device_entry); device_destroy(spidev_class, spidev->devt); clear_bit(MINOR(spidev->devt), minors); if (spidev->users == 0) kfree(spidev); mutex_unlock(&device_list_lock); Fix it by resetting spidev->spi in device_list_lock's protection. Signed-off-by: Zhenzhong Duan Link: https://lore.kernel.org/r/20200618032125.4650-1-zhenzhong.duan@gmail.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spidev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index 028725573e632..5edf4029a3486 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -782,13 +782,13 @@ static int spidev_remove(struct spi_device *spi) { struct spidev_data *spidev = spi_get_drvdata(spi); + /* prevent new opens */ + mutex_lock(&device_list_lock); /* make sure ops on existing fds can abort cleanly */ spin_lock_irq(&spidev->spi_lock); spidev->spi = NULL; spin_unlock_irq(&spidev->spi_lock); - /* prevent new opens */ - mutex_lock(&device_list_lock); list_del(&spidev->device_entry); device_destroy(spidev_class, spidev->devt); clear_bit(MINOR(spidev->devt), minors); -- 2.25.1