From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755085AbbB0TXX (ORCPT ); Fri, 27 Feb 2015 14:23:23 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:45255 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752612AbbB0TXV (ORCPT ); Fri, 27 Feb 2015 14:23:21 -0500 Date: Fri, 27 Feb 2015 11:23:18 -0800 From: Greg KH To: Jiri Slaby Cc: linux-kernel@vger.kernel.org, john_paul.perry@alcatel-lucent.com, stable@vger.kernel.org, Linus Torvalds Subject: Re: [PATCH 1/1] tty: fix up atime/mtime mess, take four Message-ID: <20150227192318.GA28610@kroah.com> References: <1425058831-13923-1-git-send-email-jslaby@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1425058831-13923-1-git-send-email-jslaby@suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 27, 2015 at 06:40:31PM +0100, Jiri Slaby wrote: > This problem was taken care of three times already in > * b0de59b5733d18b0d1974a060860a8b5c1b36a2e (TTY: do not update > atime/mtime on read/write), > * 37b7f3c76595e23257f61bd80b223de8658617ee (TTY: fix atime/mtime > regression), and > * b0b885657b6c8ef63a46bc9299b2a7715d19acde (tty: fix up atime/mtime > mess, take three) > > But it still misses one point. As John Paul correctly points out, we > do not care about setting date. If somebody ever changes wall > time backwards (by mistake for example), tty timestamps are never > updated until the original wall time passes. > > So check the absolute difference of times and if it large than "8 > seconds or so", always update the time. That means we will update > immediatelly when changing time. Ergo, CAP_SYS_TIME can foul the > check, but it was always that way. > > Thanks John for serving me this so nicely debugged. > > Signed-off-by: Jiri Slaby > Reported-by: John Paul Perry > Cc: Greg Kroah-Hartman > Cc: # all, as b0b885657 was backported > Cc: Linus Torvalds > --- > drivers/tty/tty_io.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Thanks, I'll queue this up and get it to Linus soon. greg k-h