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,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 2CBACC433DF for ; Thu, 2 Jul 2020 01:30:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B323206BE for ; Thu, 2 Jul 2020 01:30:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593653437; bh=bQdhkyleKNrB/eAmk3MoXZ4uuEJHYABQVPYga/A9WNQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=omUrg2kxzaV71M/R9NnJBKlz9gL/dBwa4o1Ofr4pMVmqxTzlQuZgAIzoOsuh74IoS f2Wq8f9W7hDO0Q3Dwb8nLOkjLckBAo1/fNRtD+Tkg6KlBfB4AOFgvbgBKGhf64Ko5X hb/S8fOswAELxYvNukGDzd8BlO7beRVvt3GFmLuw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728166AbgGBBab (ORCPT ); Wed, 1 Jul 2020 21:30:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:58666 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729318AbgGBB05 (ORCPT ); Wed, 1 Jul 2020 21:26:57 -0400 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 D5A5820748; Thu, 2 Jul 2020 01:26:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593653216; bh=bQdhkyleKNrB/eAmk3MoXZ4uuEJHYABQVPYga/A9WNQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vr6v19I9LlrkYNvq8VkGr9gi+MIU2GGYmyv4+OxeNOm7M1D5ZTBA5xKZO4AGfntd8 ANiwXfq46lTIb0Uvc+v1ZMWaZscXKcm6vtA1qzQYlDBjbXODlWgfC7i6LiPMlkFZ1s dJq/7Be+RQO7JTxNcpwKLuUFlTov48Qdz6cEganc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zhenzhong Duan , Mark Brown , Sasha Levin , linux-spi@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 05/17] spi: spidev: fix a race between spidev_release and spidev_remove Date: Wed, 1 Jul 2020 21:26:37 -0400 Message-Id: <20200702012649.2701799-5-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200702012649.2701799-1-sashal@kernel.org> References: <20200702012649.2701799-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@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