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 D8ADFC433F5 for ; Tue, 26 Oct 2021 02:43:06 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2D5BC6109E for ; Tue, 26 Oct 2021 02:43:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2D5BC6109E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Hdbj46GKKz2yfZ for ; Tue, 26 Oct 2021 13:43:04 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=srs0=c3ca=po=goodmis.org=rostedt@kernel.org; receiver=) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Hdbhc4XQ7z2xt0 for ; Tue, 26 Oct 2021 13:42:40 +1100 (AEDT) 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?= 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: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Peter Zijlstra \(Intel\)" , Paul Walmsley , "James E.J. Bottomley" , Guo Ren , Jisheng Zhang , "H. Peter Anvin" , live-patching@vger.kernel.org, linux-riscv@lists.infradead.org, Miroslav Benes , Paul Mackerras , Joe Lawrence , Helge Deller , x86@kernel.org, linux-csky@vger.kernel.org, Ingo Molnar , Petr Mladek , Albert Ou , Jiri Kosina , Nicholas Piggin , Borislav Petkov , Josh Poimboeuf , Thomas Gleixner , linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org, Palmer Dabbelt , Masami Hiramatsu , Colin Ian King , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 26 Oct 2021 10:09:12 +0800 =E7=8E=8B=E8=B4=87 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; > } >=20 > +/* > + * Preemption will be enabled (if it was previously enabled). > + */ > static __always_inline void trace_clear_recursion(int bit) > { > if (!bit) > return; >=20 > + 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), > *