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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 58E99C742BA for ; Fri, 12 Jul 2019 12:24:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 295D6216C8 for ; Fri, 12 Jul 2019 12:24:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562934250; bh=vaXuefLnQVX1WIZfUStZejGF9m9Z62dsxQs1bUacwK8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fhkYlPoj47KPpcXaPMavBe/MAcKb2DBCmFCyQ3VU4v21rv6k75ab6B1l47ybwe2os GSnuAPQ4yrVor23kgNS3njtHf5Ngkwg/G4v7064XbxJLpG+uO3N1ZKC/hHW5PGAf++ Cf9bBru9e5SZ2qgvG2D//uVTyIHdZ7lYD7KdD8ZE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728034AbfGLMYH (ORCPT ); Fri, 12 Jul 2019 08:24:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:60060 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727980AbfGLMXz (ORCPT ); Fri, 12 Jul 2019 08:23:55 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 A73122166E; Fri, 12 Jul 2019 12:23:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562934234; bh=vaXuefLnQVX1WIZfUStZejGF9m9Z62dsxQs1bUacwK8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CUQwncYpbZwDQFDUQK+yfVKx9FuqGlp/uOidx6/jNTw2n0ualSHts9AzmNfzdBPtI h09AfRfZq0Ys0y4ZMPVfEhRKj3FZPVtUR8KqOOU+J3FMHN0V/p1K55EZBn+gFILw0r d2mInNu7c+GkhmQmBzGH0mAJuVKKjb6oi/163nBs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ian Abbott Subject: [PATCH 4.19 79/91] staging: comedi: amplc_pci230: fix null pointer deref on interrupt Date: Fri, 12 Jul 2019 14:19:22 +0200 Message-Id: <20190712121626.037573937@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190712121621.422224300@linuxfoundation.org> References: <20190712121621.422224300@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Ian Abbott commit 7379e6baeddf580d01feca650ec1ad508b6ea8ee upstream. The interrupt handler `pci230_interrupt()` causes a null pointer dereference for a PCI260 card. There is no analog output subdevice for a PCI260. The `dev->write_subdev` subdevice pointer and therefore the `s_ao` subdevice pointer variable will be `NULL` for a PCI260. The following call near the end of the interrupt handler results in the null pointer dereference for a PCI260: comedi_handle_events(dev, s_ao); Fix it by only calling the above function if `s_ao` is valid. Note that the other uses of `s_ao` in the calls `pci230_handle_ao_nofifo(dev, s_ao);` and `pci230_handle_ao_fifo(dev, s_ao);` will never be reached for a PCI260, so they are safe. Fixes: 39064f23284c ("staging: comedi: amplc_pci230: use comedi_handle_events()") Cc: # v3.19+ Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/amplc_pci230.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/staging/comedi/drivers/amplc_pci230.c +++ b/drivers/staging/comedi/drivers/amplc_pci230.c @@ -2330,7 +2330,8 @@ static irqreturn_t pci230_interrupt(int devpriv->intr_running = false; spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags); - comedi_handle_events(dev, s_ao); + if (s_ao) + comedi_handle_events(dev, s_ao); comedi_handle_events(dev, s_ai); return IRQ_HANDLED;