From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1092440-1521803478-2-13414319479303461335 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521803478; b=qJE3+ll3BCTKXJgtTEDWBpToJNeECVMeA4SMPwmA+vEn1AP N449FmZXV43sZVuqin7eUuQ44e6xo+REw9QcJxT34Rkv20uqmpf6CPOHEFPfQUdO SZH7pJ5oOLeGT0LNiJqeAexh8ZNKfFwAJZzOHunMsaizovJGqkwatL6ODiEm5u43 YHJaOCMJd749904+vppKIe2kFzdBzpxPxm7zlzoju44eaVXeDvsIVBNZM3tmT+Pk F5x5WueecZMoAhY5BVwovtEnvunH7tAipFA2VjHq0LXZUgLtH5ATiBdzYQVo3QU1 EPVJeXEjvPs1ROJiWTRIVEaB5speukHAlWlYWOw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1521803478; bh=WQgnXzgY1ccboBje9nYeoefpEB BOzpfc0QXn/kstgK8=; b=gargb8KgXJitYFKosszx4Z5aUpKIAosXZDjB4XkYk0 KjsblJmYsMkdUSKadRw3OualMCE9aPb+zc9rxN+MAYHg2hpebYszktrAzT0l1aRq 578wGt12SgyK4dL48kOdBr18N6mKF0UFIBDVMeaeCBe/2KP6Sre0VuOP5Zd2aRX+ MHO5OnYlxBn4sTpIN6XzbtyYwSf9bUR+D3syr3OgcMC7yY1NPOVOAXbzXlQ3NGyP qR9+P5aVrUJeUAaZpVvRyKhUlSPEpCPWjUU6y5Ds/Isv6KWtrU2fnnioc3reMwjv PiO3gRCGBt2L2S0SBO+l6473Ji+34YjWql54qwmuiCJw== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932907AbeCWKLO (ORCPT ); Fri, 23 Mar 2018 06:11:14 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43742 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932883AbeCWKLL (ORCPT ); Fri, 23 Mar 2018 06:11:11 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Quentin Schulz , Alexandre Belloni , Sasha Levin Subject: [PATCH 4.9 151/177] rtc: ac100: Fix multiple race conditions Date: Fri, 23 Mar 2018 10:54:39 +0100 Message-Id: <20180323094211.850518911@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180323094205.090519271@linuxfoundation.org> References: <20180323094205.090519271@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexandre Belloni [ Upstream commit 994ec64c0a193940be7a6fd074668b9446d3b6c3 ] The probe function is not allowed to fail after registering the RTC 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* */ Also, the interrupt handler: ac100_rtc_irq() is dereferencing chip->rtc but this may still be NULL when it is called, resulting in: Unable to handle kernel NULL pointer dereference at virtual address 00000194 pgd = (ptrval) [00000194] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: CPU: 0 PID: 72 Comm: irq/71-ac100-rt Not tainted 4.15.0-rc1-next-20171201-dirty #120 Hardware name: Allwinner sun8i Family task: (ptrval) task.stack: (ptrval) PC is at mutex_lock+0x14/0x3c LR is at ac100_rtc_irq+0x38/0xc8 pc : [] lr : [] psr: 60000053 sp : ee9c9f28 ip : 00000000 fp : ee9adfdc r10: 00000000 r9 : c0a04c48 r8 : c015ed18 r7 : ee9bd600 r6 : ee9c9f28 r5 : ee9af590 r4 : c0a04c48 r3 : ef3cb3c0 r2 : 00000000 r1 : ee9af590 r0 : 00000194 Flags: nZCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment none Control: 10c5387d Table: 4000406a DAC: 00000051 Process irq/71-ac100-rt (pid: 72, stack limit = 0x(ptrval)) Stack: (0xee9c9f28 to 0xee9ca000) 9f20: 00000000 7c2fd1be c015ed18 ee9adf40 ee9c0400 ee9c0400 9f40: ee9adf40 c015ed34 ee9c8000 ee9adf64 ee9c0400 c015f040 ee9adf80 00000000 9f60: c015ee24 7c2fd1be ee9adfc0 ee9adf80 00000000 ee9c8000 ee9adf40 c015eef4 9f80: ef1eba34 c0138f14 ee9c8000 ee9adf80 c0138df4 00000000 00000000 00000000 9fa0: 00000000 00000000 00000000 c01010e8 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff [] (mutex_lock) from [] (ac100_rtc_irq+0x38/0xc8) [] (ac100_rtc_irq) from [] (irq_thread_fn+0x1c/0x54) [] (irq_thread_fn) from [] (irq_thread+0x14c/0x214) [] (irq_thread) from [] (kthread+0x120/0x150) [] (kthread) from [] (ret_from_fork+0x14/0x2c) Solve both issues by moving to devm_rtc_allocate_device()/rtc_register_device() Reported-by: Quentin Schulz Tested-by: Quentin Schulz Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/rtc-ac100.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) --- a/drivers/rtc/rtc-ac100.c +++ b/drivers/rtc/rtc-ac100.c @@ -567,6 +567,12 @@ static int ac100_rtc_probe(struct platfo return chip->irq; } + chip->rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(chip->rtc)) + return PTR_ERR(chip->rtc); + + chip->rtc->ops = &ac100_rtc_ops; + ret = devm_request_threaded_irq(&pdev->dev, chip->irq, NULL, ac100_rtc_irq, IRQF_SHARED | IRQF_ONESHOT, @@ -586,17 +592,16 @@ static int ac100_rtc_probe(struct platfo /* clear counter alarm pending interrupts */ regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE); - chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-ac100", - &ac100_rtc_ops, THIS_MODULE); - if (IS_ERR(chip->rtc)) { - dev_err(&pdev->dev, "unable to register device\n"); - return PTR_ERR(chip->rtc); - } - ret = ac100_rtc_register_clks(chip); if (ret) return ret; + ret = rtc_register_device(chip->rtc); + if (ret) { + dev_err(&pdev->dev, "unable to register device\n"); + return ret; + } + dev_info(&pdev->dev, "RTC enabled\n"); return 0;