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 A23D9C433B4 for ; Mon, 3 May 2021 15:55:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64FD3610C8 for ; Mon, 3 May 2021 15:55:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231138AbhECP42 (ORCPT ); Mon, 3 May 2021 11:56:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230236AbhECP4Z (ORCPT ); Mon, 3 May 2021 11:56:25 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70EEFC06174A for ; Mon, 3 May 2021 08:55:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+Vs0E/3wz3OQ4L5AnkU+ZgKdk9Ar5MBuRPGlKkIQNpE=; b=IOd8I0LIVnLrc0EybvWIy8xbaJ RazRbWdsTUUdwOd9euV7Rkw1fHjEcoTRqZEHV5zDApHuaruTUnk+2cWpEIskOp+9C7cWD3wiOUkeW GBNg9vxDAScezGoeWemV+gwz8lceYTDu6QBQxTpJ+MnnsIh8wJ5WZ4TAl4dlfBg55YMDL6XpM8y4M /MXx6bORsR6UDUJMLZp4lLgHhAZEobRT56enGT5d8R3/Rv6elyTTcmAl4lFbyCtvuIvjiYmRsOOO5 It/YZInPf/mOloaXo8bzPmwtrzZHJj/qDNCGVWALFtBkT+Z2KAxL+uO9o3rBYsFXBvAG58HPobTB/ XuUaAFVA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1ldauj-00EJIl-DT; Mon, 03 May 2021 15:55:17 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 69B2C300036; Mon, 3 May 2021 17:55:16 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 1AEED20D77EEE; Mon, 3 May 2021 17:55:16 +0200 (CEST) Date: Mon, 3 May 2021 17:55:16 +0200 From: Peter Zijlstra To: Steven Rostedt Cc: Hillf Danton , syzbot , linux-kernel@vger.kernel.org, Oleg Nesterov , syzkaller-bugs@googlegroups.com, Jiri Olsa Subject: Re: [syzbot] possible deadlock in vm_mmap_pgoff Message-ID: References: <000000000000217d7005c0f5c6b1@google.com> <20210428061522.1841-1-hdanton@sina.com> <20210428093018.70c3888b@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210428093018.70c3888b@gandalf.local.home> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 28, 2021 at 09:30:18AM -0400, Steven Rostedt wrote: > > Break the lock chain by asking kworker to destroy perf event. > > Thoughts other than workqueue are appreciated. > > I think this could cause a problem with the delay. > > This is called from event->destroy() > > > if (event->destroy) > event->destroy(event); > module_put(pmu->module); The uprobe and tracepoint pmus will never be a module.