From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753924AbaC3XdM (ORCPT ); Sun, 30 Mar 2014 19:33:12 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36504 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753143AbaC3XZE (ORCPT ); Sun, 30 Mar 2014 19:25:04 -0400 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, "Greg Kroah-Hartman" , "Ian Abbott" , "Dan Carpenter" Date: Mon, 31 Mar 2014 00:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 178/200] staging: comedi: pcmuio: fix possible NULL deref on detach In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.56-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit 2fd2bdfccae61efe18f6b92b6a45fbf936d75b48 upstream. pcmuio_detach() is called by the comedi core even if pcmuio_attach() returned an error, so `dev->private` might be `NULL`. Check for that before dereferencing it. Also, as pointed out by Dan Carpenter, there is no need to check the pointer passed to `kfree()` is non-NULL, so remove that check. Signed-off-by: Ian Abbott Cc: Dan Carpenter Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/staging/comedi/drivers/pcmuio.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/staging/comedi/drivers/pcmuio.c b/drivers/staging/comedi/drivers/pcmuio.c index 661ba2e..6e936c5 100644 --- a/drivers/staging/comedi/drivers/pcmuio.c +++ b/drivers/staging/comedi/drivers/pcmuio.c @@ -464,13 +464,13 @@ static int pcmuio_detach(struct comedi_device *dev) if (dev->iobase) release_region(dev->iobase, ASIC_IOSIZE * thisboard->num_asics); - for (i = 0; i < MAX_ASICS; ++i) { - if (devpriv->asics[i].irq) - free_irq(devpriv->asics[i].irq, dev); - } - - if (devpriv && devpriv->sprivs) + if (devpriv) { + for (i = 0; i < MAX_ASICS; ++i) { + if (devpriv->asics[i].irq) + free_irq(devpriv->asics[i].irq, dev); + } kfree(devpriv->sprivs); + } return 0; }