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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 085FDC4332F for ; Tue, 26 Oct 2021 02:42:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E17886109E for ; Tue, 26 Oct 2021 02:42:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234441AbhJZCpC convert rfc822-to-8bit (ORCPT ); Mon, 25 Oct 2021 22:45:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:56450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234432AbhJZCpA (ORCPT ); Mon, 25 Oct 2021 22:45:00 -0400 Received: from rorschach.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 E000861074; Tue, 26 Oct 2021 02:42:34 +0000 (UTC) Date: Mon, 25 Oct 2021 22:42:33 -0400 From: Steven Rostedt To: =?UTF-8?B?546L6LSH?= Cc: Guo Ren , Ingo Molnar , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Thomas Gleixner , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Colin Ian King , Masami Hiramatsu , "Peter Zijlstra (Intel)" , Nicholas Piggin , Jisheng Zhang , linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, live-patching@vger.kernel.org Subject: Re: [PATCH v4 0/2] fix & prevent the missing preemption disabling Message-ID: <20211025224233.61b8e088@rorschach.local.home> In-Reply-To: <71c21f78-9c44-fdb2-f8e2-d8544b3421bd@linux.alibaba.com> References: <32a36348-69ee-6464-390c-3a8d6e9d2b53@linux.alibaba.com> <71c21f78-9c44-fdb2-f8e2-d8544b3421bd@linux.alibaba.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On Tue, 26 Oct 2021 10:09:12 +0800 王贇 wrote: > Just a ping, to see if there are any more comments :-P I guess you missed what went into mainline (and your name found a bug in my perl script for importing patches ;-) https://lore.kernel.org/all/20211019091344.65629198@gandalf.local.home/ Which means patch 1 needs to change: > + /* > + * Disable preemption to fulfill the promise. > + * > + * Don't worry about the bit 0 cases, they indicate > + * the disabling behaviour has already been done by > + * internal call previously. > + */ > + preempt_disable_notrace(); > + > return bit + 1; > } > > +/* > + * Preemption will be enabled (if it was previously enabled). > + */ > static __always_inline void trace_clear_recursion(int bit) > { > if (!bit) > return; > > + if (bit > 0) > + preempt_enable_notrace(); > + Where this wont work anymore. Need to preempt disable and enable always. -- Steve > barrier(); > bit--; > trace_recursion_clear(bit); > @@ -209,7 +227,7 @@ static __always_inline void trace_clear_recursion(int bit) > * tracing recursed in the same context (normal vs interrupt), > *