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=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7CCDEC433DF for ; Fri, 21 Aug 2020 11:25:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4EF332072D for ; Fri, 21 Aug 2020 11:25:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SHzB0lz7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726610AbgHULZL (ORCPT ); Fri, 21 Aug 2020 07:25:11 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:33276 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727912AbgHULU4 (ORCPT ); Fri, 21 Aug 2020 07:20:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598008850; h=from:from:reply-to:subject:subject: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=TVZPy7+N9bwrhLBiHBDmf2ilfdv7OW35jUfwMGWMLck=; b=SHzB0lz7EyE/uEYinPhsDvRB22EtHEnozzssZuJe5sfWxAlqG4ZhGTLpN21xlu4l55hqXb C6Tfkv0MX+Taj16O5/Yz/nFA5IuBng1qFpJfKeAjlLGmOGwczCoM4kAwNDapzrjFld38TN xqdVCp6mRRT9IqIPiK4mvE/PK/WuUsI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-191-mLtxB508OFynLZExQXVzIg-1; Fri, 21 Aug 2020 07:20:46 -0400 X-MC-Unique: mLtxB508OFynLZExQXVzIg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A16E1100CED1; Fri, 21 Aug 2020 11:20:44 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.192.73]) by smtp.corp.redhat.com (Postfix) with SMTP id 0DA705F705; Fri, 21 Aug 2020 11:20:42 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 21 Aug 2020 13:20:44 +0200 (CEST) Date: Fri, 21 Aug 2020 13:20:41 +0200 From: Oleg Nesterov To: Davidlohr Bueso Cc: akpm@linux-foundation.org, catalin.marinas@arm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Davidlohr Bueso Subject: Re: [PATCH] mm/kmemleak: rely on rcu for task stack scanning Message-ID: <20200821112041.GH4546@redhat.com> References: <20200820203902.11308-1-dave@stgolabs.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200820203902.11308-1-dave@stgolabs.net> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/20, Davidlohr Bueso wrote: > > @@ -1471,15 +1471,15 @@ static void kmemleak_scan(void) > if (kmemleak_stack_scan) { > struct task_struct *p, *g; > > - read_lock(&tasklist_lock); > - do_each_thread(g, p) { > + rcu_read_lock(); > + for_each_process_thread(g, p) { > void *stack = try_get_task_stack(p); > if (stack) { > scan_block(stack, stack + THREAD_SIZE, NULL); > put_task_stack(p); > } > - } while_each_thread(g, p); > - read_unlock(&tasklist_lock); > + } > + rcu_read_unlock(); Acked-by: Oleg Nesterov