From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754891Ab2AaTQB (ORCPT ); Tue, 31 Jan 2012 14:16:01 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:33323 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752898Ab2AaTQA (ORCPT ); Tue, 31 Jan 2012 14:16:00 -0500 Date: Tue, 31 Jan 2012 11:15:53 -0800 From: Andrew Morton To: Arnd Bergmann Cc: Samuel Thibault , linux-kernel@vger.kernel.org, "Greg Kroah-Hartman" , Arthur Taylor , Jiri Slaby , Jiri Olsa Subject: Re: [PATCH] Fix KDFONTOP 32bit compatibility layer Message-Id: <20120131111553.e69ab58b.akpm@linux-foundation.org> In-Reply-To: <201201311635.36367.arnd@arndb.de> References: <20120128232858.GA18484@type.famille.thibault.fr> <201201311635.36367.arnd@arndb.de> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 31 Jan 2012 16:35:36 +0000 Arnd Bergmann wrote: > On Saturday 28 January 2012, Samuel Thibault wrote: > > KDFONTOP(GET) currently fails with EIO when being run in a 32bit > > userland with a 64bit kernel if the font width is not 8. This is because > > the compatibility layer introduced by e9216651 forces the addition of > > the KD_FONT_FLAG_OLD flag, which makes con_font_get return EIO in such > > case. This flag should not be set for KDFONTOP, since it's actually > > the whole point of this flag (see comment in con_font_set for instance). > > > > Signed-off-by: Samuel Thibault > > Hmm, this flag was not introduced in the patch you cite, it used to > live in fs/compat_ioctl.c before that, since before the start of the > git history. It seems to date back on the original sparc64 implementation > of do_kdfontop_ioctl that was written by Eddie Dost in 1998. > > > diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c > > index 5e096f4..65447c5 100644 > > --- a/drivers/tty/vt/vt_ioctl.c > > +++ b/drivers/tty/vt/vt_ioctl.c > > @@ -1463,7 +1463,6 @@ compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop, > > if (!perm && op->op != KD_FONT_OP_GET) > > return -EPERM; > > op->data = compat_ptr(((struct compat_console_font_op *)op)->data); > > - op->flags |= KD_FONT_FLAG_OLD; > > i = con_font_op(vc, op); > > if (i) > > return i; > > From all I can tell, the patch looks correct, but please update the > description so you don't blame my innocent patch ;-) > > Reviewed-by: Arnd Bergmann Yes, we should note the fact that at least one kernel bug isn't your fault ;) I changed the changelog to : KDFONTOP(GET) currently fails with EIO when being run in a 32bit userland : with a 64bit kernel if the font width is not 8. : : This is because of the setting of the KD_FONT_FLAG_OLD flag, which makes : con_font_get return EIO in such case. : : This flag should *not* be set for KDFONTOP, since it's actually the whole : point of this flag (see comment in con_font_set for instance). : : Signed-off-by: Samuel Thibault : Reviewed-by: Arnd Bergmann : Cc: Greg Kroah-Hartman : Cc: Arthur Taylor : Cc: Jiri Slaby : Cc: Jiri Olsa : Cc: