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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 085AEC4332D for ; Fri, 20 Mar 2020 05:10:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEE9220739 for ; Fri, 20 Mar 2020 05:10:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584681052; bh=bHqz/mmjyWz7y2CbYXKF3rlS2vNGxaJf7CYZ9FIl/Hc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=wVmsZKYQoY5r8RAbGgCO4QUmrtXA3gZ1aalFaGhGOoMnay6XxNSgg4ntT3Mw9QHN4 n4l0eKcIGdOs3vCLzOAv6tOBwjJIF7qlcQ5uD+J6HSfT5M1rzp+QBz10ChwjW5BHhD vQkhDIbFEXTXtrsmUH97UEDAtvobUZ8+1aglFr6k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726030AbgCTFKw (ORCPT ); Fri, 20 Mar 2020 01:10:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:59420 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725883AbgCTFKw (ORCPT ); Fri, 20 Mar 2020 01:10:52 -0400 Received: from sol.localdomain (c-107-3-166-239.hsd1.ca.comcast.net [107.3.166.239]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 05DE12072D; Fri, 20 Mar 2020 05:10:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584681051; bh=bHqz/mmjyWz7y2CbYXKF3rlS2vNGxaJf7CYZ9FIl/Hc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CS+AMu4Ldrf5EQrnN3qqOyzcwytupsd2xi8te7S9EclBM61mvUsK4Ty8Ax7mBMCL4 JrRgTSfUZMEg0PH+nsGHFpcp9255sLia17GXV7e0lwLANmIZg5fIe0HcAz1VnEFoNM EZeQ0BASP2vftBfk6DI/UUBTAVFxJ3Wqo5/e0Rkg= Date: Thu, 19 Mar 2020 22:10:49 -0700 From: Eric Biggers To: Jiri Slaby Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, syzkaller-bugs@googlegroups.com, Eric Dumazet , Nicolas Pitre Subject: Re: [PATCH v2 1/2] vt: vt_ioctl: fix VT_DISALLOCATE freeing in-use virtual console Message-ID: <20200320051049.GA1315@sol.localdomain> References: <20200318222704.GC2334@sol.localdomain> <20200318223810.162440-1-ebiggers@kernel.org> <20200318223810.162440-2-ebiggers@kernel.org> <2f762aee-720b-9bec-620f-61129c724de6@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2f762aee-720b-9bec-620f-61129c724de6@suse.com> Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Thu, Mar 19, 2020 at 08:36:28AM +0100, Jiri Slaby wrote: > On 18. 03. 20, 23:38, Eric Biggers wrote: > > --- a/drivers/tty/vt/vt.c > > +++ b/drivers/tty/vt/vt.c > > @@ -1102,6 +1102,9 @@ int vc_allocate(unsigned int currcons) /* return 0 on success */ > > tty_port_init(&vc->port); > > INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK); > > > > + /* if this wasn't the case, we'd have to implement port->ops.destruct */ > > + BUILD_BUG_ON(offsetof(struct vc_data, port) != 0); > > + > > This is 3 lines, implementing destruct would be like 4-5 :)? Please > implement destruct instead. > > Otherwise looks good. > Actually implementing destruct would be 12 lines, see below. Remember there is no tty_port_operations defined yet so we'd have to define it just for destruct. Do you still prefer it? diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index ec34f1f5f3bb5..309a39197be0a 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -1075,6 +1075,17 @@ static void visual_deinit(struct vc_data *vc) module_put(vc->vc_sw->owner); } +static void vc_port_destruct(struct tty_port *port) +{ + struct vc_data *vc = container_of(port, struct vc_data, port); + + kfree(vc); +} + +static const struct tty_port_operations vc_port_ops = { + .destruct = vc_port_destruct, +}; + int vc_allocate(unsigned int currcons) /* return 0 on success */ { struct vt_notifier_param param; @@ -1100,11 +1111,9 @@ int vc_allocate(unsigned int currcons) /* return 0 on success */ vc_cons[currcons].d = vc; tty_port_init(&vc->port); + vc->port.ops = &vc_port_ops; INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK); - /* if this wasn't the case, we'd have to implement port->ops.destruct */ - BUILD_BUG_ON(offsetof(struct vc_data, port) != 0); - visual_init(vc, currcons, 1); if (!*vc->vc_uni_pagedir_loc)