From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45946 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404264AbeHATDh (ORCPT ); Wed, 1 Aug 2018 15:03:37 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexandre Belloni , Sasha Levin Subject: [PATCH 4.17 160/336] rtc: vr41xx: fix possible race condition Date: Wed, 1 Aug 2018 18:48:15 +0200 Message-Id: <20180801165035.239056093@linuxfoundation.org> In-Reply-To: <20180801165028.930831994@linuxfoundation.org> References: <20180801165028.930831994@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexandre Belloni [ Upstream commit 9a99247c9c1d1c95c6e8153d013979aac6111c6e ] The probe function is not allowed to fail after the RTC is registered because the following may happen: CPU0: CPU1: sys_load_module() do_init_module() do_one_initcall() cmos_do_probe() rtc_device_register() __register_chrdev() cdev->owner = struct module* open("/dev/rtc0") rtc_device_unregister() module_put() free_module() module_free(mod->module_core) /* struct module *module is now freed */ chrdev_open() spin_lock(cdev_lock) cdev_get() try_module_get() module_is_live() /* dereferences already freed struct module* */ Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/rtc-vr41xx.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/drivers/rtc/rtc-vr41xx.c +++ b/drivers/rtc/rtc-vr41xx.c @@ -292,13 +292,14 @@ static int rtc_probe(struct platform_dev goto err_rtc1_iounmap; } - rtc = devm_rtc_device_register(&pdev->dev, rtc_name, &vr41xx_rtc_ops, - THIS_MODULE); + rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(rtc)) { retval = PTR_ERR(rtc); goto err_iounmap_all; } + rtc->ops = &vr41xx_rtc_ops; + rtc->max_user_freq = MAX_PERIODIC_RATE; spin_lock_irq(&rtc_lock); @@ -340,6 +341,10 @@ static int rtc_probe(struct platform_dev dev_info(&pdev->dev, "Real Time Clock of NEC VR4100 series\n"); + retval = rtc_register_device(rtc); + if (retval) + goto err_iounmap_all; + return 0; err_iounmap_all: