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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 BE784ECE561 for ; Thu, 20 Sep 2018 06:40:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7564621525 for ; Thu, 20 Sep 2018 06:40:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7564621525 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-pci-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731305AbeITMWr (ORCPT ); Thu, 20 Sep 2018 08:22:47 -0400 Received: from verein.lst.de ([213.95.11.211]:57873 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731240AbeITMWr (ORCPT ); Thu, 20 Sep 2018 08:22:47 -0400 Received: by newverein.lst.de (Postfix, from userid 2407) id 72D5E68D79; Thu, 20 Sep 2018 08:40:55 +0200 (CEST) Date: Thu, 20 Sep 2018 08:40:55 +0200 From: Christoph Hellwig To: Bjorn Helgaas Cc: Tonghao Zhang , linux-pci@vger.kernel.org, Christoph Hellwig Subject: Re: kernel panic becase pci register more than once Message-ID: <20180920064055.GH12913@lst.de> References: <20180917191503.GA54859@bhelgaas-glaptop.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180917191503.GA54859@bhelgaas-glaptop.roam.corp.google.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Sep 17, 2018 at 02:15:03PM -0500, Bjorn Helgaas wrote: > A WARN_ON() shouldn't cause the kernel to panic. Do you mean that it > causes a backtrace? I think that's the intended behavior, because > calling this twice would be a driver bug, and we want to find and fix > those bugs. > > > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c > > index f2ef896..324840f 100644 > > --- a/drivers/pci/msi.c > > +++ b/drivers/pci/msi.c > > @@ -958,7 +958,9 @@ static int __pci_enable_msix(struct pci_dev *dev, > > struct msix_entry *entries, > > } > > } > > } > > - WARN_ON(!!dev->msix_enabled); > > + > > + if (dev->msix_enabled) > > + return -EINVAL; This is a grave driver bug, so we should keep a trace. Then again handling even grave driver bugs more gracefull is a good idea, so I'd vote for: if (WARN_ON_ONCE(dev->msix_enabled)) return -EINVAL;