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=-8.0 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 B76ACC433ED for ; Wed, 12 May 2021 14:39:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67441613E9 for ; Wed, 12 May 2021 14:39:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230473AbhELOka (ORCPT ); Wed, 12 May 2021 10:40:30 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:58104 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230247AbhELOk3 (ORCPT ); Wed, 12 May 2021 10:40:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620830361; 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=vC+DDiLBvCP950gYw38LBndpncTBiw4wY9B/u7aFc6k=; b=YYqX1CDyg8vh0BGZDCFwr+eHLtoml35z0SvZp/tuxgZoyfHVTK3aICKpRocfTxab5ivZXP tywyy7GT/qfhF+ho0VnkpgPySL1CWSwkwDxIvsCW4Zw0TQCgygA2j8fE65sMfrcv3JS5GB ZYu7i0lyLJBRE2PzXDSKGAp8xylXNII= 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-183-CdNKbv3jNGag5bGdSZ3fsA-1; Wed, 12 May 2021 10:39:19 -0400 X-MC-Unique: CdNKbv3jNGag5bGdSZ3fsA-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 F1623104FB62; Wed, 12 May 2021 14:39:16 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.193.76]) by smtp.corp.redhat.com (Postfix) with SMTP id A42655C8AA; Wed, 12 May 2021 14:38:57 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 12 May 2021 16:39:16 +0200 (CEST) Date: Wed, 12 May 2021 16:38:56 +0200 From: Oleg Nesterov To: Mathieu Desnoyers Cc: Linus Torvalds , Andrew Morton , "Eric W. Biederman" , Eugene Syromiatnikov , Jan Kratochvil , Michael Kerrisk , Pedro Alves , Simon Marchi , linux-kernel Subject: Re: [PATCH RESEND2] ptrace: make ptrace() fail if the tracee changed its pid unexpectedly Message-ID: <20210512143855.GB19594@redhat.com> References: <20210511165626.GA13720@redhat.com> <20210511175341.GA14488@redhat.com> <20210511180627.GB14488@redhat.com> <20210512133615.GA19594@redhat.com> <1879292286.40455.1620827809948.JavaMail.zimbra@efficios.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1879292286.40455.1620827809948.JavaMail.zimbra@efficios.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mathieu, On 05/12, Mathieu Desnoyers wrote: > > Out of curiosity: what makes it OK to use either the current task or its > parent's pid namespace in this specific case ? What happens if they are > in different pid namespaces ? Because in this case current == task->parent == debugger. Just in case... task->real_parent is, well, "real parent", the parent which forked this task. task->parent == task->real_parent unless this task is ptraced, in this case task->parent == debugger. Oleg.