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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY 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 9517BC43603 for ; Sun, 8 Dec 2019 09:44:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6324E206D6 for ; Sun, 8 Dec 2019 09:44:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726450AbfLHJoW (ORCPT ); Sun, 8 Dec 2019 04:44:22 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:50234 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725878AbfLHJoV (ORCPT ); Sun, 8 Dec 2019 04:44:21 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: ezequiel) with ESMTPSA id AA5A728A186 Message-ID: Subject: Re: [PATCH] media: davinci/vpfe_capture.c: Avoid BUG_ON for register failure From: Ezequiel Garcia To: Aditya Pakki Cc: kjlu@umn.edu, "Lad, Prabhakar" , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Date: Sun, 08 Dec 2019 06:44:11 -0300 In-Reply-To: References: <20191206010029.14265-1-pakki001@umn.edu> Organization: Collabora Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Aditya, On Fri, 2019-12-06 at 06:20 -0300, Ezequiel Garcia wrote: > Hello Aditya, > > Thanks for the patch. > > On Thu, 2019-12-05 at 19:00 -0600, Aditya Pakki wrote: > > In vpfe_register_ccdc_device(), failure to allocate dev->hw_ops > > invokes calls to BUG_ON(). This patch returns the error to callers > > instead of crashing. > > > > I'm curious, are you actually getting this type of crash? > Oops, it seems I was too fast to say this looked good. The driver is not dynamically allocating dev->hw_ops; as you can see hw_ops is not a pointer. struct ccdc_hw_device { /* ccdc device name */ char name[32]; /* module owner */ struct module *owner; /* hw ops */ struct ccdc_hw_ops hw_ops; }; Please, don't submit patches without testing, at the very least compile testing. Thanks, Ezequiel > > Signed-off-by: Aditya Pakki > > --- > > drivers/media/platform/davinci/vpfe_capture.c | 21 ++++++------------- > > 1 file changed, 6 insertions(+), 15 deletions(-) > > > > diff --git a/drivers/media/platform/davinci/vpfe_capture.c b/drivers/media/platform/davinci/vpfe_capture.c > > index 916ed743d716..6d394a006977 100644 > > --- a/drivers/media/platform/davinci/vpfe_capture.c > > +++ b/drivers/media/platform/davinci/vpfe_capture.c > > @@ -168,21 +168,11 @@ int vpfe_register_ccdc_device(const struct ccdc_hw_device *dev) > > int ret = 0; > > printk(KERN_NOTICE "vpfe_register_ccdc_device: %s\n", dev->name); > > > > - BUG_ON(!dev->hw_ops.open); > > - BUG_ON(!dev->hw_ops.enable); > > - BUG_ON(!dev->hw_ops.set_hw_if_params); > > - BUG_ON(!dev->hw_ops.configure); > > - BUG_ON(!dev->hw_ops.set_buftype); > > - BUG_ON(!dev->hw_ops.get_buftype); > > - BUG_ON(!dev->hw_ops.enum_pix); > > - BUG_ON(!dev->hw_ops.set_frame_format); > > - BUG_ON(!dev->hw_ops.get_frame_format); > > - BUG_ON(!dev->hw_ops.get_pixel_format); > > - BUG_ON(!dev->hw_ops.set_pixel_format); > > - BUG_ON(!dev->hw_ops.set_image_window); > > - BUG_ON(!dev->hw_ops.get_image_window); > > - BUG_ON(!dev->hw_ops.get_line_length); > > - BUG_ON(!dev->hw_ops.getfid); > > + if (!dev->hw_ops) { > > + printk(KERN_ERR "could not allocate hw_ops\n"); > > I'd drop this error message, as hw_ops is not really allocated here. > > > + ret = -EINVAL; > > + goto rvalue; > > Instead of a goto to a return, just return -EINVAL here. > > > + } > > > > mutex_lock(&ccdc_lock); > > if (!ccdc_cfg) { > > @@ -211,6 +201,7 @@ int vpfe_register_ccdc_device(const struct ccdc_hw_device *dev) > > ccdc_dev = dev; > > unlock: > > mutex_unlock(&ccdc_lock); > > +rvalue: > > return ret; > > } > > EXPORT_SYMBOL(vpfe_register_ccdc_device); > > With those changes, the patch looks good. > > Reviewed-by: Ezequiel Garcia > > Thanks, > Ezequiel >