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=-2.4 required=3.0 tests=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 6D7D0C17442 for ; Wed, 13 Nov 2019 13:42:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4207F22459 for ; Wed, 13 Nov 2019 13:42:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="U1bRV0hG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727577AbfKMNmT (ORCPT ); Wed, 13 Nov 2019 08:42:19 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:20321 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726434AbfKMNmS (ORCPT ); Wed, 13 Nov 2019 08:42:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573652536; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JgU2e8RT59hEaQw/a6iawkjHzbdgc0u0v1JZhhfT5kU=; b=U1bRV0hGlhzyn7KIa2MD0bWHh1j91mybyLpqcIIFndulbD3A4AEbf1yDiuyM6FUfdejAsw mPa/quPq2dzOQtcJFyNnByi1IND5L/ESWTOiRm6bfK6iwfh+0+AfOFhqN0mHXGFm9V1ftV jDl7+cHeo1QjKfMMIL6rWFmhB9ouUvU= 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-231-nY7xI--DNa61pN8DDiLq6g-1; Wed, 13 Nov 2019 08:42:13 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D08391852E20; Wed, 13 Nov 2019 13:42:10 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.44]) by smtp.corp.redhat.com (Postfix) with SMTP id BD3972B7C5; Wed, 13 Nov 2019 13:42:08 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 13 Nov 2019 14:42:09 +0100 (CET) Date: Wed, 13 Nov 2019 14:42:06 +0100 From: Oleg Nesterov To: Adrian Reber Cc: Christian Brauner , Eric Biederman , Pavel Emelyanov , Jann Horn , Dmitry Safonov <0x7f454c46@gmail.com>, Rasmus Villemoes , linux-kernel@vger.kernel.org, Andrei Vagin , Mike Rapoport , Radostin Stoyanov Subject: Re: [PATCH v8 1/2] fork: extend clone3() to support setting a PID Message-ID: <20191113134206.GA4320@redhat.com> References: <20191113080301.1197762-1-areber@redhat.com> MIME-Version: 1.0 In-Reply-To: <20191113080301.1197762-1-areber@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: nY7xI--DNa61pN8DDiLq6g-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/13, Adrian Reber wrote: > > @@ -175,23 +187,47 @@ struct pid *alloc_pid(struct pid_namespace *ns) > =20 > =09for (i =3D ns->level; i >=3D 0; i--) { > =09=09int pid_min =3D 1; Well, this is really minor but again, pid_min is only used in the "else" branch below, you can move this declaration there. > + > +=09=09if (set_tid_size) { > +=09=09=09tid =3D set_tid[ns->level - i]; > +=09=09=09if (tid < 1 || tid >=3D pid_max) > +=09=09=09=09return ERR_PTR(-EINVAL); > +=09=09=09/* Also fail if a PID !=3D 1 is requested and no PID 1 exists *= / > +=09=09=09if (tid !=3D 1 && !tmp->child_reaper) > +=09=09=09=09return ERR_PTR(-EINVAL); > +=09=09=09if (!ns_capable(tmp->user_ns, CAP_SYS_ADMIN)) > +=09=09=09=09return ERR_PTR(-EPERM); > +=09=09} > =20 > =09=09idr_preload(GFP_KERNEL); > =09=09spin_lock_irq(&pidmap_lock); > =20 > -=09=09/* > -=09=09 * init really needs pid 1, but after reaching the maximum > -=09=09 * wrap back to RESERVED_PIDS > -=09=09 */ > -=09=09if (idr_get_cursor(&tmp->idr) > RESERVED_PIDS) > -=09=09=09pid_min =3D RESERVED_PIDS; > - > -=09=09/* > -=09=09 * Store a null pointer so find_pid_ns does not find > -=09=09 * a partially initialized PID (see below). > -=09=09 */ > -=09=09nr =3D idr_alloc_cyclic(&tmp->idr, NULL, pid_min, > -=09=09=09=09 pid_max, GFP_ATOMIC); > +=09=09if (tid) { > +=09=09=09nr =3D idr_alloc(&tmp->idr, NULL, tid, > +=09=09=09=09 tid + 1, GFP_ATOMIC); > +=09=09=09/* > +=09=09=09 * If ENOSPC is returned it means that the PID is > +=09=09=09 * alreay in use. Return EEXIST in that case. > +=09=09=09 */ > +=09=09=09if (nr =3D=3D -ENOSPC) > +=09=09=09=09nr =3D -EEXIST; > +=09=09=09set_tid_size--; ^^^^^^^^^^^^^^^ May I ask you to move this decrement into the "if (set_tid_size)" block abo= ve? Oleg.