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=-16.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 5BFBFC432BE for ; Thu, 26 Aug 2021 10:54:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34E28610A1 for ; Thu, 26 Aug 2021 10:54:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241722AbhHZKzG (ORCPT ); Thu, 26 Aug 2021 06:55:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:52200 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234296AbhHZKzF (ORCPT ); Thu, 26 Aug 2021 06:55:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A207160FC1; Thu, 26 Aug 2021 10:54:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1629975258; bh=3COvzkeM/l1x3SVib6kbANwKzq1rzz8/bNWnK5LJTh4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OjjbqPrErjAAwn/gK0egjwHkX1sjV9lqg3PgbElLuWvQZ/vtg3onfAeeqjepK+Jwk IxkzDexi1m+XzGInKdti3lY4O1igyftWtPppa4u2dZHvFNwFDfrJn8jKu4lLLiLY3w UoQwkqbfKGIxIWM+dcHdUv635O9ta7UMdSCEmbgU= Date: Thu, 26 Aug 2021 12:54:14 +0200 From: Greg Kroah-Hartman To: Woody Lin Cc: Todd Kjos , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Martijn Coenen , Joel Fernandes , Christian Brauner , Hridya Valsaraju , Suren Baghdasaryan , linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev Subject: Re: [PATCH] ANDROID: staging: add userpanic-dev driver Message-ID: References: <20210826092854.58694-1-woodylin@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 26, 2021 at 06:23:53PM +0800, Woody Lin wrote: > On Thu, Aug 26, 2021 at 5:48 PM Greg Kroah-Hartman > wrote: > > > > On Thu, Aug 26, 2021 at 05:28:54PM +0800, Woody Lin wrote: > > > Add char device driver 'userpanic-dev' that exposes an interface to > > > userspace processes to request a system panic with customized panic > > > message. > > > > > > Signed-off-by: Woody Lin > > > --- > > > drivers/staging/android/Kconfig | 12 +++ > > > drivers/staging/android/Makefile | 1 + > > > drivers/staging/android/userpanic-dev.c | 110 ++++++++++++++++++++++++ > > > > Why is this in staging? What is wrong with it that it can not just go > > into the real part of the kernel? A TODO file is needed explaining what > > needs to be done here in order for it to be accepted. > > Got it. No more TODO for this driver and I will move it to drivers/android/. > > > > > But why is this really needed at all? Why would userspace want to panic > > the kernel in yet-another-way? > > The idea is to panic the kernel with a panic message specified by the userspace > process requesting the panic. Without this the panic handler can only collect > panic message "sysrq triggered crash" for a panic triggered by user processes. > Using this driver, user processes can put an informative description - > process name, > reason ...etc. - to the panic message. What custom userspace tool is going to use this new user/kernel api and again, why is it needed? Who needs to panic the kernel with a custom message and where is that used? thanks, greg k-h