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 37F01C433E5 for ; Mon, 20 Jul 2020 15:41:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 084D12176B for ; Mon, 20 Jul 2020 15:41:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595259665; bh=lY5i/G1xFnqXCzRAHXjROM97QoklifLMJB3E/TZuJmw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1d+AAIiS2zBjZmV6exHrq9AeIjmEXa2nxh6ctve8D0ZWjZd4oQ0Dny0j3Fx0UmvfV iErtzr6k2dbo4bNthHH9R2gBJMge6BJLD3GXrLbaJIA5OCUVizrDAp1mef9B4DKk4c gKx5vroTt1VuTfJModC/phCCOFnBM0jxfGnp0nPg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728650AbgGTPlD (ORCPT ); Mon, 20 Jul 2020 11:41:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:60540 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729081AbgGTPkx (ORCPT ); Mon, 20 Jul 2020 11:40:53 -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 A02E720773; Mon, 20 Jul 2020 15:40:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595259653; bh=lY5i/G1xFnqXCzRAHXjROM97QoklifLMJB3E/TZuJmw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l0hKs0YnVcMPquNZSKSpSY0wOFhdOMFT3C3yoroL5+Ne4VA6XA5ZR+mgN6c0GykKu tgDBV1K2NXGTORnQIYz8uoI3rJTYVIl/67Q14GJBy25lcc0Lj1ZxhTuDw/fGVt9h3F W4/cS2AQitPtzahdaSxrLqtXNA3uzdHcuskvdxtU= 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 4.9 03/86] spi: spidev: fix a race between spidev_release and spidev_remove Date: Mon, 20 Jul 2020 17:35:59 +0200 Message-Id: <20200720152753.305614900@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200720152753.138974850@linuxfoundation.org> References: <20200720152753.138974850@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 a685c6114a8d5..67ad7e46da42d 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -809,13 +809,13 @@ 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