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 78EBAC433DF for ; Thu, 2 Jul 2020 01:33:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56FE72082F for ; Thu, 2 Jul 2020 01:33:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593653630; bh=ZaXnKVv036WIEZxAKuXBF80BGpN2iXc9gZtAy+/Mtrc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CTUyIOaSxjC1x8gg5TPIPl7S3xNyp6e6B0+rUAWFLFsJJh8eKEP9qMw2ho3QL1Dup Dn8C7eeWcgP3zu1gTH6LrMikmFegtTfUi0pbZrzIdsLVulFIF7Oo06krX8tk1xEBb9 JibDV3lw1cOcnMp0MCxHu2Y9103Q1/Z3e5L6GN9I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728893AbgGBBZo (ORCPT ); Wed, 1 Jul 2020 21:25:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:56758 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728225AbgGBBZo (ORCPT ); Wed, 1 Jul 2020 21:25:44 -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 E4D5020B1F; Thu, 2 Jul 2020 01:25:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593653143; bh=ZaXnKVv036WIEZxAKuXBF80BGpN2iXc9gZtAy+/Mtrc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ly66Cl8c/NSoqvSmgJdAgnZPyZsmJ09a483yJvFui76vu4RLW/C4vdrNk8WN8yWqH JYgHPmpns4Uywv9XztZIjSI0O6nxdzbkcnnTY5C7F+DeIHd/gySRS+ZajIEEh4J3ZP /1nfdDAOC6xhsY4EZVme6deP8m++GvsC7fo5nbt8= 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 5.4 15/40] spi: spidev: fix a race between spidev_release and spidev_remove Date: Wed, 1 Jul 2020 21:23:36 -0400 Message-Id: <20200702012402.2701121-15-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200702012402.2701121-1-sashal@kernel.org> References: <20200702012402.2701121-1-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 ab2c3848f5bf8..88d0976215fac 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -783,13 +783,13 @@ 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