From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 2B5522C68C for ; Mon, 5 Feb 2024 14:56:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707145019; cv=none; b=RYhvsP9TihzkDUhKVQEaiYrLSwKn7Btg3OaZRU4wqGss8zHrplWY5UqgI7yU1YUzWaN1hOQRbbm60pjS3a49Wu7bvKvIHB+agE43HQZSq2+3Jhm6X4V10cXX237IOjouVDI09Oe99ETfeHPndlCF1NknGxL/ihVLsHJw3ftUacc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707145019; c=relaxed/simple; bh=yml1g8lIUP8NOhlaf1UJ6FHxeNTEQqWwTozbd2chOzM=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=e3Z+pigT3Uj5zVAeuvmoJna+TMmqIm7rascMkrNcu63FiL6ngWfwxTKNWM4NI7E6bLTtPdvA2lW3vwods4JZx8PZqflRQmwlGYNus99D8kgFBOe3CIE0v6PFeUltkUpfpnsvb/RJSrQK04isnuD2ZjdxkPhCIcXe2dzqP0R/m1Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=CD2vQ05r; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="CD2vQ05r" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707145015; 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; bh=3wWFKFwgxakmvKvguQj6wEaI43mBgwyBm4UjoRgLEUY=; b=CD2vQ05rHYQ+o8Yg7hOq5voDSLH/Hr99N8QdIdjanEpG74rnysUEtyswydSp+xTT0IlfJP ZKlXz5ziTOLmTIsdtKZo7W6R92Ghu18+iFClgoJe1bDxRRg2z5emQY3xMs5wQI5lduQDbj r40Pt5RxFdQRuVShxXnrpmDjBnY+6kU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-220-nvK2DcrVMjCHItX-V9VBBA-1; Mon, 05 Feb 2024 09:56:51 -0500 X-MC-Unique: nvK2DcrVMjCHItX-V9VBBA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (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 6801C8432A3; Mon, 5 Feb 2024 14:56:50 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.225.165]) by smtp.corp.redhat.com (Postfix) with SMTP id BC7FB3C2E; Mon, 5 Feb 2024 14:56:48 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 5 Feb 2024 15:55:34 +0100 (CET) Date: Mon, 5 Feb 2024 15:55:32 +0100 From: Oleg Nesterov To: Christian Brauner Cc: Andy Lutomirski , "Eric W. Biederman" , Tycho Andersen , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] pidfd: clone: allow CLONE_THREAD | CLONE_PIDFD together Message-ID: <20240205145532.GA28823@redhat.com> Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 copy_process() just needs to pass PIDFD_THREAD to __pidfd_prepare() if clone_flags & CLONE_THREAD. We can also add another CLONE_ flag (or perhaps reuse CLONE_DETACHED) to enforce PIDFD_THREAD without CLONE_THREAD. Originally-from: Tycho Andersen Signed-off-by: Oleg Nesterov --- kernel/fork.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index 8d08a2d1b095..cd61ca87d0e6 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2311,9 +2311,8 @@ __latent_entropy struct task_struct *copy_process( /* * - CLONE_DETACHED is blocked so that we can potentially * reuse it later for CLONE_PIDFD. - * - CLONE_THREAD is blocked until someone really needs it. */ - if (clone_flags & (CLONE_DETACHED | CLONE_THREAD)) + if (clone_flags & CLONE_DETACHED) return ERR_PTR(-EINVAL); } @@ -2536,8 +2535,10 @@ __latent_entropy struct task_struct *copy_process( * if the fd table isn't shared). */ if (clone_flags & CLONE_PIDFD) { + int flags = (clone_flags & CLONE_THREAD) ? PIDFD_THREAD : 0; + /* Note that no task has been attached to @pid yet. */ - retval = __pidfd_prepare(pid, 0, &pidfile); + retval = __pidfd_prepare(pid, flags, &pidfile); if (retval < 0) goto bad_fork_free_pid; pidfd = retval; -- 2.25.1.362.g51ebf55