From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ysx3+T/m" Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7BCCD7D for ; Thu, 30 Nov 2023 11:43:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701373403; 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=1LzR82TZZoRBH/QGAZ8DY5Aa+itdrUDM4gzCDXUwKhE=; b=Ysx3+T/mVS7pVHYhsAKoKYAU0y5Ntu1UafkmpBaQWyhyuJvIvdyph86BBZGhosznfS6fkH dGCe/fP0FDfPh5ZAzumfDlXiALW3kpUje4IPTsmGQVh4cP4/Y2SRnvhKQOOPL/sCvtAiHD wmZjFPB+Qm3QsTCLuha101Llh/d0QiM= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-673-HioBAyClOBG-ZY4j2hqARw-1; Thu, 30 Nov 2023 14:43:22 -0500 X-MC-Unique: HioBAyClOBG-ZY4j2hqARw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id AB73B381CBA1; Thu, 30 Nov 2023 19:43:21 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.45]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 046491121307; Thu, 30 Nov 2023 19:43:19 +0000 (UTC) From: Florian Weimer To: Mathieu Desnoyers Cc: Tycho Andersen , Christian Brauner , Oleg Nesterov , "Eric W . Biederman" , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Tycho Andersen Subject: Re: [RFC 1/3] pidfd: allow pidfd_open() on non-thread-group leaders References: <20231130163946.277502-1-tycho@tycho.pizza> <874jh3t7e9.fsf@oldenburg.str.redhat.com> Date: Thu, 30 Nov 2023 20:43:18 +0100 In-Reply-To: (Mathieu Desnoyers's message of "Thu, 30 Nov 2023 14:00:01 -0500") Message-ID: <87ttp3rprd.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.3 (gnu/linux) Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 * Mathieu Desnoyers: >>> I'd like to offer a userspace API which allows safe stashing of >>> unreachable file descriptors on a service thread. >> By "safe" here do you mean not accessible via pidfd_getfd()? No, unreachable by close/close_range/dup2/dup3. I expect we can do an intra-process transfer using /proc, but I'm hoping for something nicer. Thanks, Florian