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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 B189AC4321A for ; Fri, 28 Jun 2019 17:33:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C637208C4 for ; Fri, 28 Jun 2019 17:33:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561743215; bh=YxLIbKTsXkeNGBeOgLGxsdbSlVn+lJmPvWdqZxXTY9o=; h=Date:From:To:cc:Subject:In-Reply-To:References:List-ID:From; b=kwYm+xDpmYPyMPC40cEZTctYSWQAb/GJm7uYHIAD7ydkpGZ/n2tS6dR7pcavWBiiN 0ZW0sWf0bQKDdi/f7A+l4JWLmpfg4AA6ZPZT0jQzvi/BfckF823am1uMK9yXA/5rUw U9e+h1cnGyUi/hYbcLMx/qrcoJhR95IWbva/jgJ0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726472AbfF1Rdf (ORCPT ); Fri, 28 Jun 2019 13:33:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:43608 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726408AbfF1Rdf (ORCPT ); Fri, 28 Jun 2019 13:33:35 -0400 Received: from pobox.suse.cz (prg-ext-pat.suse.com [213.151.95.130]) (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 51963205F4; Fri, 28 Jun 2019 17:33:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561743214; bh=YxLIbKTsXkeNGBeOgLGxsdbSlVn+lJmPvWdqZxXTY9o=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=lZNM7yCzcrOSyI3/CgtnTokCk4mMR6mCJmdqoLmYGM1WM5otsXUNnnQEp0vRhmrDq Be6O2NjBK4O85riWi67JSswsP7XxCWR0O1K3HXuuZBuHKlfc3bHbbL1+oloZqOWHdA fDE89s425UzPn+xbOWWKx4qBmOuMM6jiJ7/fUSYE= Date: Fri, 28 Jun 2019 19:33:30 +0200 (CEST) From: Jiri Kosina To: Josh Poimboeuf cc: Thomas Gleixner , Steven Rostedt , Petr Mladek , Miroslav Benes , Jessica Yu , Joe Lawrence , linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, Johannes Erdfelt , Ingo Molnar , mhiramat@kernel.org, torvalds@linux-foundation.org Subject: Re: [PATCH] ftrace: Remove possible deadlock between register_kprobe() and ftrace_run_update_code() In-Reply-To: <20190627231952.nqkbtcculvo2ddif@treble> Message-ID: References: <20190627081334.12793-1-pmladek@suse.com> <20190627224729.tshtq4bhzhneq24w@treble> <20190627190457.703a486e@gandalf.local.home> <20190627231952.nqkbtcculvo2ddif@treble> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: live-patching-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Thu, 27 Jun 2019, Josh Poimboeuf wrote: > > How is that supposed to work? > > > > ftrace > > prepare() > > setrw() > > setro() > > patch <- FAIL > > /me dodges frozen shark > > You are right of course. My brain has apparently already shut off for > the day. > > Maybe a comment or two would help though. I'd actually prefer (perhaps in parallel to the comment) using the __acquires() and __releases() anotations, so that sparse and friends don't get confused by that either. -- Jiri Kosina SUSE Labs