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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 C2813C433E3 for ; Thu, 16 Jul 2020 19:15:07 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 0C42C2065F for ; Thu, 16 Jul 2020 19:15:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="GFAY7/qF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C42C2065F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19359-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 3097 invoked by uid 550); 16 Jul 2020 19:15:01 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 2041 invoked from network); 16 Jul 2020 19:15:00 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=DmwAjlYrRkrceLF5k8BiY0q5EpRy1ms1f0jDcB2PX04=; b=GFAY7/qFyIYdH5WwlOR6lmpQdUB8pidv4p+YEiNNV+24D6QE2wlS74FWkZdBInZexv UOIim5XchmtCaZ3l4TQzzuOzonn1fB1BUMbSjBEdmwtfVzMcmZFxfBS2TADWV5S1ZbJV +LUOh6KntXrSBKz4ZwAcXC+80++YNoPqG5L4s= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=DmwAjlYrRkrceLF5k8BiY0q5EpRy1ms1f0jDcB2PX04=; b=Q7tyr0R395JMa1Ciy5AWI6HlkTfjTWsLCdFU67IE3XYydV8uZGP304LkaJ9qh3RiQ2 Lpwcbj9ebDKXgAbcNrltSmIM/Mt7JTSpe7oZrHSvMbi+tdWOOU1aM88UN78Wem46qAFp d/qqmlggUZafx9d0/920dJtixGLsgsX4nxPzfMMFcnW0uLcZI8i2w5tseZRyV6R6J7QO 9wGu8XtUWl19xYozZ2De67xjETFQU0z6IqyJXUjfrkdgDcYo0Sr7HXvhtQPNL6naxWnB 5xqSBwwDTxkggLTReyfLJYNWCiVTXC/7MX5TTSKv8NXJN6lETHl5WZp2OVjsGhzRRTRy G6yw== X-Gm-Message-State: AOAM5300LtBsrZ4R5Izl0D5aspn2uKDDqII8WYtY3uLTU6ODjijYDUmI x5SO5HAlzi0JZhVLZFzf31VbFQ== X-Google-Smtp-Source: ABdhPJzXMzbyTY5VJHPd4Edm3bSGjXJUJOwIzo3RSPKyMSZOc846WSYGarDg6OCvj6pUTCBmbdFM0Q== X-Received: by 2002:a17:90a:318c:: with SMTP id j12mr6129543pjb.25.1594926888230; Thu, 16 Jul 2020 12:14:48 -0700 (PDT) Date: Thu, 16 Jul 2020 12:14:46 -0700 From: Kees Cook To: Peter Zijlstra Cc: Greg Kroah-Hartman , Thomas Gleixner , Allen Pais , Oscar Carter , Romain Perier , Dmitry Torokhov , Kevin Curtis , "David S. Miller" , Jakub Kicinski , Harald Freudenberger , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Jiri Slaby , Felipe Balbi , Jason Wessel , Daniel Thompson , Douglas Anderson , Mitchell Blank Jr , Julian Wiedmann , Karsten Graul , Ursula Braun , Jaroslav Kysela , Takashi Iwai , Christian Gromm , Nishka Dasgupta , Masahiro Yamada , Stephen Boyd , "Matthew Wilcox (Oracle)" , Wambui Karuga , Guenter Roeck , Chris Packham , Kyungtae Kim , Kuppuswamy Sathyanarayanan , Sebastian Andrzej Siewior , "Rafael J. Wysocki" , Jonathan Corbet , Will Deacon , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, devel@driverdev.osuosl.org, linux-usb@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, alsa-devel@alsa-project.org, kernel-hardening@lists.openwall.com Subject: Re: [PATCH 0/3] Modernize tasklet callback API Message-ID: <202007161214.102F6E6@keescook> References: <20200716030847.1564131-1-keescook@chromium.org> <20200716075718.GM10769@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200716075718.GM10769@hirez.programming.kicks-ass.net> On Thu, Jul 16, 2020 at 09:57:18AM +0200, Peter Zijlstra wrote: > On Wed, Jul 15, 2020 at 08:08:44PM -0700, Kees Cook wrote: > > Hi, > > > > This is the infrastructure changes to prepare the tasklet API for > > conversion to passing the tasklet struct as the callback argument instead > > of an arbitrary unsigned long. The first patch details why this is useful > > (it's the same rationale as the timer_struct changes from a bit ago: > > less abuse during memory corruption attacks, more in line with existing > > ways of doing things in the kernel, save a little space in struct, > > etc). Notably, the existing tasklet API use is much less messy, so there > > is less to clean up. > > I would _MUCH_ rather see tasklets go the way of the dodo, esp. given > that: > > > drivers/input/keyboard/omap-keypad.c | 2 +- > > drivers/input/serio/hil_mlc.c | 2 +- > > drivers/net/wan/farsync.c | 4 +-- > > drivers/s390/crypto/ap_bus.c | 2 +- > > drivers/staging/most/dim2/dim2.c | 2 +- > > drivers/staging/octeon/ethernet-tx.c | 2 +- > > drivers/tty/vt/keyboard.c | 2 +- > > drivers/usb/gadget/udc/snps_udc_core.c | 6 ++--- > > drivers/usb/host/fhci-sched.c | 2 +- > > include/linux/interrupt.h | 37 ++++++++++++++++++++++---- > > kernel/backtracetest.c | 2 +- > > kernel/debug/debug_core.c | 2 +- > > kernel/irq/resend.c | 2 +- > > kernel/softirq.c | 18 ++++++++++++- > > net/atm/pppoatm.c | 2 +- > > net/iucv/iucv.c | 2 +- > > sound/drivers/pcsp/pcsp_lib.c | 2 +- > > 17 files changed, 66 insertions(+), 25 deletions(-) > > there appear to be hardly any users left.. Can't we stage an extinction > event here instead? Oh, I wish, but no. That's just the ones using DECLARE_TASKLET. There are hundred(s?) more (see the referenced tree). -- Kees Cook