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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 92FD7C169C4 for ; Sun, 3 Feb 2019 13:58:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B7A62084A for ; Sun, 3 Feb 2019 13:58:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729239AbfBCN6p (ORCPT ); Sun, 3 Feb 2019 08:58:45 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:53724 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728337AbfBCNt7 (ORCPT ); Sun, 3 Feb 2019 08:49:59 -0500 Received: from cable-78.29.236.164.coditel.net ([78.29.236.164] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gqI9k-0003tu-SU; Sun, 03 Feb 2019 13:49:57 +0000 Received: from ben by deadeye with local (Exim 4.92-RC4) (envelope-from ) id 1gqI9g-0007At-35; Sun, 03 Feb 2019 14:49:52 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Greg Kroah-Hartman" , "Dan Carpenter" , "Mathias Thore" Date: Sun, 03 Feb 2019 14:45:08 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 186/305] uio: Fix an Oops on load In-Reply-To: X-SA-Exim-Connect-IP: 78.29.236.164 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter commit 432798195bbce1f8cd33d1c0284d0538835e25fb upstream. I was trying to solve a double free but I introduced a more serious NULL dereference bug. The problem is that if there is an IRQ which triggers immediately, then we need "info->uio_dev" but it's not set yet. This patch puts the original initialization back to how it was and just sets info->uio_dev to NULL on the error path so it should solve both the Oops and the double free. Fixes: f019f07ecf6a ("uio: potential double frees if __uio_register_device() fails") Reported-by: Mathias Thore Signed-off-by: Dan Carpenter Tested-by: Mathias Thore Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/uio/uio.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -852,14 +852,17 @@ int __uio_register_device(struct module if (ret) goto err_uio_dev_add_attributes; + info->uio_dev = idev; + if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) { ret = devm_request_irq(idev->dev, info->irq, uio_interrupt, info->irq_flags, info->name, idev); - if (ret) + if (ret) { + info->uio_dev = NULL; goto err_request_irq; + } } - info->uio_dev = idev; return 0; err_request_irq: