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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 4D185C433DB for ; Thu, 4 Mar 2021 09:58:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B556464F20 for ; Thu, 4 Mar 2021 09:58:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B556464F20 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E3CA66B0005; Thu, 4 Mar 2021 04:58:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DECB76B0006; Thu, 4 Mar 2021 04:58:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C714C6B0007; Thu, 4 Mar 2021 04:58:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0160.hostedemail.com [216.40.44.160]) by kanga.kvack.org (Postfix) with ESMTP id A84F26B0005 for ; Thu, 4 Mar 2021 04:58:42 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 5203618030353 for ; Thu, 4 Mar 2021 09:58:42 +0000 (UTC) X-FDA: 77881742484.14.A22D1F6 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf25.hostedemail.com (Postfix) with ESMTP id ACD276000102 for ; Thu, 4 Mar 2021 09:58:40 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1614851920; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=H+Vq6O5olw4xwzFFe299bnHsHIPKz6DwZZTvQIM7UXI=; b=dcjhF6ZddsuBWbaL5ro/UgiOqUChdTPrHDEPRNSD/qq8sZjhOZwUIkeEBeZMk7djvS9ObH aib6thLKpuC6Y6PzdEASMjpkPsT0aUW3I2ZMFtrFuCXUI4aICBVXd4gKPEenYNekdBanWE 0Jmp9iPZoPErJCKO2BQ9yko9dFVybVA= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3D56CAD74; Thu, 4 Mar 2021 09:58:40 +0000 (UTC) Date: Thu, 4 Mar 2021 10:58:39 +0100 From: Michal Hocko To: "Paul E. McKenney" Cc: Mike Kravetz , Shakeel Butt , syzbot , Andrew Morton , LKML , Linux MM , syzkaller-bugs , Eric Dumazet , Mina Almasry , tglx@linutronix.de, john.ogness@linutronix.de, urezki@gmail.com, ast@fb.com Subject: Re: possible deadlock in sk_clone_lock Message-ID: References: <122e8c5d-60b8-52d9-c6a1-00cd61b2e1b6@oracle.com> <06edda9a-dce9-accd-11a3-97f6d5243ed1@oracle.com> <20210303175945.GE2696@paulmck-ThinkPad-P72> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210303175945.GE2696@paulmck-ThinkPad-P72> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: ACD276000102 X-Stat-Signature: skdwapxbpz69ws5jfr5t48zaaczfi3rf Received-SPF: none (suse.com>: No applicable sender policy available) receiver=imf25; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614851920-717566 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 03-03-21 09:59:45, Paul E. McKenney wrote: > On Wed, Mar 03, 2021 at 09:03:27AM +0100, Michal Hocko wrote: [...] > > Paul what is the current plan with in_atomic to be usable for !PREEMPT > > configurations? > > Ah, thank you for the reminder! I have rebased that series on top of > v5.12-rc1 on -rcu branch tglx-pc.2021.03.03a. > > The current state is that Linus is not convinced that this change is > worthwhile given that only RCU and printk() want it. (BPF would use > it if it were available, but is willing to live without it, at least in > the short term.) > > But maybe Linus will be convinced given your additional use case. > Here is hoping! Yes, hugetlb freeing path would benefit from this. You can reference this lockdep report (http://lkml.kernel.org/r/000000000000f1c03b05bc43aadc@google.com) with an additional argument that making hugetlb_lock irq safe is a larger undertaking and we will need something reasonably backportable for older kernels as well. -- Michal Hocko SUSE Labs