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=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 832D7C43441 for ; Mon, 19 Nov 2018 16:57:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C7F9208E3 for ; Mon, 19 Nov 2018 16:57:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="a6Lf2XvS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C7F9208E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404564AbeKTDVs (ORCPT ); Mon, 19 Nov 2018 22:21:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:33266 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403956AbeKTDVr (ORCPT ); Mon, 19 Nov 2018 22:21:47 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 563A321104; Mon, 19 Nov 2018 16:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542646651; bh=N1nPlVEsOp+A0RAXnlFRp57z6gIlAcJTkcsrnkeYkj0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a6Lf2XvSdDzApPFi0miX4rWMTjH0Yu/zicxUMvyIK/LB+4EQZkh9TKDFJvYOi6rKk SR6EhF+MBjs21s1OgSpa1EfN74PwZJv0aj1bFIdLhVupc54nRdqWYeR++qMJTsDnyc 3RtZjPQShtp3GCwfokJARmpkMBmT0VfPoom1SfhA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexandre Belloni , Sasha Levin Subject: [PATCH 4.4 039/160] uio: ensure class is registered before devices Date: Mon, 19 Nov 2018 17:27:58 +0100 Message-Id: <20181119162634.950080295@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181119162630.031306128@linuxfoundation.org> References: <20181119162630.031306128@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexandre Belloni [ Upstream commit ae61cf5b9913027c6953a79ed3894da4f47061bd ] When both uio and the uio drivers are built in the kernel, it is possible for a driver to register devices before the uio class is registered. This may result in a NULL pointer dereference later on in get_device_parent() when accessing the class glue_dirs spinlock. The trace looks like that: Unable to handle kernel NULL pointer dereference at virtual address 00000140 [...] [] _raw_spin_lock+0x14/0x48 [] device_add+0x154/0x6a0 [] device_create_groups_vargs+0x120/0x128 [] device_create+0x54/0x60 [] __uio_register_device+0x120/0x4a8 [] jaguar2_pci_probe+0x2d4/0x558 [] local_pci_probe+0x3c/0xb8 [] pci_device_probe+0x11c/0x180 [] driver_probe_device+0x22c/0x2d8 [] __driver_attach+0xbc/0xc0 [] bus_for_each_dev+0x4c/0x98 [] driver_attach+0x20/0x28 [] bus_add_driver+0x1b8/0x228 [] driver_register+0x60/0xf8 [] __pci_register_driver+0x40/0x48 Return EPROBE_DEFER in that case so the driver can register the device later. Signed-off-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/uio/uio.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -249,6 +249,8 @@ static struct class uio_class = { .dev_groups = uio_groups, }; +bool uio_class_registered; + /* * device functions */ @@ -772,6 +774,9 @@ static int init_uio_class(void) printk(KERN_ERR "class_register failed for uio\n"); goto err_class_register; } + + uio_class_registered = true; + return 0; err_class_register: @@ -782,6 +787,7 @@ exit: static void release_uio_class(void) { + uio_class_registered = false; class_unregister(&uio_class); uio_major_cleanup(); } @@ -801,6 +807,9 @@ int __uio_register_device(struct module struct uio_device *idev; int ret = 0; + if (!uio_class_registered) + return -EPROBE_DEFER; + if (!parent || !info || !info->name || !info->version) return -EINVAL;