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 D0814C43217 for ; Tue, 26 Oct 2021 02:52:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBF3A610A1 for ; Tue, 26 Oct 2021 02:52:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234481AbhJZCzN (ORCPT ); Mon, 25 Oct 2021 22:55:13 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:34834 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233160AbhJZCzM (ORCPT ); Mon, 25 Oct 2021 22:55:12 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R691e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=31;SR=0;TI=SMTPD_---0Utj7nbU_1635216761; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0Utj7nbU_1635216761) by smtp.aliyun-inc.com(127.0.0.1); Tue, 26 Oct 2021 10:52:42 +0800 Subject: Re: [PATCH v4 0/2] fix & prevent the missing preemption disabling To: Steven Rostedt 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 References: <32a36348-69ee-6464-390c-3a8d6e9d2b53@linux.alibaba.com> <71c21f78-9c44-fdb2-f8e2-d8544b3421bd@linux.alibaba.com> <20211025224233.61b8e088@rorschach.local.home> From: =?UTF-8?B?546L6LSH?= Message-ID: Date: Tue, 26 Oct 2021 10:52:41 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <20211025224233.61b8e088@rorschach.local.home> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/10/26 上午10:42, Steven Rostedt wrote: > On Tue, 26 Oct 2021 10:09:12 +0800 > ηŽ‹θ΄‡ 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/ Cool~ Missing some chinese font maybe, that's fine :-) > > 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. Yup, will rebase on the latest changes~ Regards, Michael Wang > > -- 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), >> *