From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E1B5473195 for ; Tue, 6 Feb 2024 13:38:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707226713; cv=none; b=nIE5s3Tsu733ayaECgg0QkMMbwRogFLoJh49k7JFZxQdgR8VrLoGBqftj7ilj9G0sZF9sK0xXYq4WcKClNt4G/kDYS6+8+brE6lKq1gWjIFX/07duDqyc/gcitjl2xgFHBSRy+aGeDMPLkdIlfAjW79RSe05I/55ijMqsevBAic= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707226713; c=relaxed/simple; bh=Fb1RR5YKjdb++HKdFCbp1Gw0EkAjp8M6VBIziUToSwE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UXWAB4EEUEW3JHniTCGOhJG+Ba/IOb4YzkTAy9lNuIl2bV+U/b5vkTY8tONjvZJBCoBE7Dg8O5NkxJLI+KYSXDJz+7idE9Sd4SrxrqXJRs6et/Bqy4RfIVRXyOHMsl2gWhVHHUDP0GeTbMraAOJBhL+oqnoStHNZ1Q+psPtacHs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WbN7uTfZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WbN7uTfZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17472C433F1; Tue, 6 Feb 2024 13:38:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707226712; bh=Fb1RR5YKjdb++HKdFCbp1Gw0EkAjp8M6VBIziUToSwE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WbN7uTfZXwr134Sf3PejpCzdftQv7Bju4pbmqRNmVB8cm0Si1/6QSOj7OpJVPVglf +TBuluksaWSHVZcwVRPJeAfgRPkxLYRma2Ds8NCDjvPOgoM0ZKm7IDwWi9lmaohYzf 3jKzja2+ibFv6rhPRBkriY/bRsv+diPEuOWFVZYPAt073JnKzAmvKMjuy3afg/JSrp vc4mFs55R/oiGViAyPi+e2M8dU5/9KsyEHHxn7moLy9qFOhj8n+05Bzq6hXd04j4zQ sQalc5QtlxCz52mgGI2DL+LhKDEm4y+zRP7gNyO3v2dLp8znwa6ObM/YElHCoB3FS5 m6nurpyFmEGkQ== Date: Tue, 6 Feb 2024 14:38:28 +0100 From: Christian Brauner To: Oleg Nesterov Cc: "Eric W. Biederman" , Tycho Andersen , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/1] pidfd: implement PIDFD_THREAD flag for pidfd_open() Message-ID: <20240206-beatmen-lehrling-440dc305b070@brauner> References: <20240131132541.GA23632@redhat.com> <20240131132602.GA23641@redhat.com> <20240202-helium-eurem-f63c0f9328c0@brauner> <20240205152241.GB15853@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240205152241.GB15853@redhat.com> On Mon, Feb 05, 2024 at 04:22:41PM +0100, Oleg Nesterov wrote: > On 02/02, Christian Brauner wrote: > > > > > @@ -2050,6 +2051,8 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) > > > > > > seq_put_decimal_ll(m, "Pid:\t", nr); > > > > > > + /* TODO: report PIDFD_THREAD */ > > > > So I think we don't need to do anything here. Since PIDFD_THREAD sets > > O_EXCL in file->f_flags and in contrast to do_dentry_open() it isn't > > dropped. So userspace can already detect PIDFD_NONBLOCK as O_NONBLOCK > > and PIDFD_THREAD as O_EXCL. > > Ah, indeed, I didn't know that fs/proc/fd.c:seq_show() reports ->f_flags. > Thanks. > > > > OK, what about another TODO in sys_pidfd_send_signal() ? > > I mean, should I send a simple patch which changes pidfd_send_signal() > to use do_send_specific() if PIDFD_THREAD ? Or do you think this should Yes, by default the type of pidfd should determine the scope of the signal as discussed elsewhere. (And later we can add flags that allow the caller to change the scope of the signal. So that Andy's use-cases are covered as well.)