Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751200AbWBUXH1 (ORCPT ); Tue, 21 Feb 2006 18:07:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751205AbWBUXH1 (ORCPT ); Tue, 21 Feb 2006 18:07:27 -0500 Received: from zproxy.gmail.com ([64.233.162.203]:5997 "EHLO zproxy.gmail.com") by vger.kernel.org with ESMTP id S1751200AbWBUXH0 convert rfc822-to-8bit (ORCPT ); Tue, 21 Feb 2006 18:07:26 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=F8wpAwsZT9j5vVWhleOkzX7IV1cg8r6AoovY7vV/fONiVO8ZjTm/jG7euTjz2hS2k/YeSxrJPblphpdfpHkAmDwP45BqWbNGE/tRKM1kQbBmASB1cTIVKTEyTQJxD9B9khRDB6EyrkbWPOWz0tTLXHGkNq5gMGAldI3GQ56P66o= Message-ID: <9a8748490602211507t26b42420s50f8e7a227f485b4@mail.gmail.com> Date: Wed, 22 Feb 2006 00:07:25 +0100 From: "Jesper Juhl" To: "Jesper Juhl" , linux-kernel@vger.kernel.org, "Andrew Morton" , "Karsten Keil" , "Kai Germaschewski" , isdn4linux@listserv.isdn4linux.de Subject: Re: [PATCH] ISDN: fix copy_to_user() unused result warning in isdn_ppp In-Reply-To: <20060221230346.GA17973@pingi.kke.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <200602212314.15362.jesper.juhl@gmail.com> <20060221230346.GA17973@pingi.kke.suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2603 Lines: 76 On 2/22/06, Karsten Keil wrote: > On Tue, Feb 21, 2006 at 11:14:15PM +0100, Jesper Juhl wrote: > > From: Jesper Juhl > > > > > > Fix compile warning about copy_to_user() unused result in isdn_ppp.c > > drivers/isdn/i4l/isdn_ppp.c:785: warning: ignoring return value of `copy_to_user', declared with attribute warn_unused_result > > > > > > Signed-off-by: Jesper Juhl > > > > --- > > > > drivers/isdn/i4l/isdn_ppp.c | 5 ++++- > > 1 files changed, 4 insertions(+), 1 deletion(-) > > > > --- linux-2.6.16-rc4-mm1-orig/drivers/isdn/i4l/isdn_ppp.c 2006-01-03 04:21:10.000000000 +0100 > > +++ linux-2.6.16-rc4-mm1/drivers/isdn/i4l/isdn_ppp.c 2006-02-21 23:07:57.000000000 +0100 > > @@ -782,7 +782,10 @@ isdn_ppp_read(int min, struct file *file > > is->first = b; > > > > spin_unlock_irqrestore(&is->buflock, flags); > > - copy_to_user(buf, save_buf, count); > > + if (copy_to_user(buf, save_buf, count)) { > > + kfree(save_buf); > > + return -EFAULT; > > + } > > kfree(save_buf); > > > > return count; > > What about: > > --- linux-2.6.16-rc4-mm1-orig/drivers/isdn/i4l/isdn_ppp.c 2006-01-03 04:21:10.000000000 +0100 > +++ linux-2.6.16-rc4-mm1/drivers/isdn/i4l/isdn_ppp.c 2006-02-21 23:07:57.000000000 +0100 > @@ -782,7 +782,8 @@ isdn_ppp_read(int min, struct file *file > is->first = b; > > spin_unlock_irqrestore(&is->buflock, flags); > - copy_to_user(buf, save_buf, count); > + if (copy_to_user(buf, save_buf, count)) > + count = -EFAULT; > kfree(save_buf); > > return count; > > should result in a conditional move instead of jumps. > I actually considered that, but decided against it since I thought it would be confusing use / misuse of 'count'. Either version is fine by me. It's not likely to get hit in any case due to the verify_area() call further up in the code. > But I'm OK with the original patch as well, for both version you can add > > Signed-off-by: Karsten Keil > Thanks. Andrew: could you please apply either my or Karsten's version to -mm ? -- Jesper Juhl Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please http://www.expita.com/nomime.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/