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 97268C433FE for ; Thu, 14 Oct 2021 12:03:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 79421610EA for ; Thu, 14 Oct 2021 12:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230198AbhJNMFI (ORCPT ); Thu, 14 Oct 2021 08:05:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34516 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230172AbhJNMFH (ORCPT ); Thu, 14 Oct 2021 08:05:07 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06FD4C061570; Thu, 14 Oct 2021 05:03:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=LQbu81zuvorNbNl7md+JgKHR7v/3E2/nFaDHpBUMKHE=; b=K+VqEeAQrYdM6TmqnvgqR8nQZ2 NUVGVVdJOKwbDDGJLr2XaNah8D3QzuwIEiRxNHZTCkRVBNPcsYGoyUwvsSFUkI26FQ57xybfxRkBr xIKCPhafKP5jWU8T3MrrEwNDfJlZ9qcmPxjI6L5P1Fyyd6l7J+c0+vDz8E4JQB8gBWwekKorq1TPB mTkG7hJstKx4fg034oRxe7rWHPayvwIpCm8kaC3EoNrDKi410bqJjM+2qNJuGSsLX8FJgTReiQ0Ke nvz5uY+7YlYlxuOcmgx+88lfZbqgtns6SWmoBoNUKgfH5gijloXLdNXfI3Cl4FyDKOoCE2NzAHUpf +RdYfERQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:55094) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mazRg-0001Ib-Rt; Thu, 14 Oct 2021 13:02:48 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1mazRS-00028C-K9; Thu, 14 Oct 2021 13:02:34 +0100 Date: Thu, 14 Oct 2021 13:02:34 +0100 From: "Russell King (Oracle)" To: Peter Zijlstra Cc: keescook@chromium.org, jannh@google.com, linux-kernel@vger.kernel.org, vcaputo@pengaru.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, amistry@google.com, Kenta.Tada@sony.com, legion@kernel.org, michael.weiss@aisec.fraunhofer.de, mhocko@suse.com, deller@gmx.de, zhengqi.arch@bytedance.com, me@tobin.cc, tycho@tycho.pizza, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, mark.rutland@arm.com, axboe@kernel.dk, metze@samba.org, laijs@linux.alibaba.com, luto@kernel.org, dave.hansen@linux.intel.com, ebiederm@xmission.com, ohoono.kwon@samsung.com, kaleshsingh@google.com, yifeifz2@illinois.edu, jpoimboe@redhat.com, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, vgupta@kernel.org, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, jonas@southpole.se, mpe@ellerman.id.au, paul.walmsley@sifive.com, hca@linux.ibm.com, ysato@users.sourceforge.jp, davem@davemloft.net, chris@zankel.net Subject: Re: [PATCH 0/7] wchan: Fix wchan support Message-ID: References: <20211008111527.438276127@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211008111527.438276127@infradead.org> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Fri, Oct 08, 2021 at 01:15:27PM +0200, Peter Zijlstra wrote: > Hi, > > This fixes up wchan which is various degrees of broken across the > architectures. > > Patch 4 fixes wchan for x86, which has been returning 0 for the past many > releases. > > Patch 5 fixes the fundamental race against scheduling. > > Patch 6 deletes a lot and makes STACKTRACE unconditional > > patch 7 fixes up a few STACKTRACE arch oddities > > 0day says all builds are good, so it must be perfect :-) I'm planning on > queueing up at least the first 5 patches, but I'm hoping the last two patches > can be too. > > Also available here: > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/wchan These patches introduce a regression on ARM. Whereas before, I have /proc/*/wchan populated with non-zero values, with these patches they _all_ contain "0": root@clearfog21:~# cat /proc/*/wchan 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000root@clearfog21:~# I'll try to investigate what is going on later today. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!