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=-8.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 98DDBC43613 for ; Thu, 20 Jun 2019 18:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6EFF920665 for ; Thu, 20 Jun 2019 18:33:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561055585; bh=Q3Y+jTMtwJ6igER/h8jL54dZxpdJqUUZCd15E/OgiYU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AQWBqzGT10Kn0+NILSi3ty4ye3V4mwRDwtREquKkjoBG9wda+s6yo7J1gLTYHRnVW K7sgmeuwfkyLk27rj5lIf7mQnDA+zQb4M36C4+c9Rq4OQFTD88JMTJ9g7UPQPbd2Yl oyShGUuvbBtokTZ0H/2v2n3gE/NcHy95KzUQWgyQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726045AbfFTR61 (ORCPT ); Thu, 20 Jun 2019 13:58:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:45152 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725815AbfFTR6Z (ORCPT ); Thu, 20 Jun 2019 13:58:25 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 97F68208CA; Thu, 20 Jun 2019 17:58:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561053505; bh=Q3Y+jTMtwJ6igER/h8jL54dZxpdJqUUZCd15E/OgiYU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dbzbrKLhFOipFxjvmZLW5NppCZ9CUYPD0fRt7AZ/EHsR5AuTick0hnmYbWJPrl9Sv Te7gGQWjx5IVyTMHBSKghu9bOqFNuUzVBc9xjbKbZ1opxujTYpcmtRsK8LpxlMNP0O U9zl7qW9zhJOg4PnTPV2AINNORiT5WonEIjjjfVY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ondrej Mosnacek , Miroslav Lichvar , Thomas Gleixner , John Stultz , Richard Cochran , Prarit Bhargava , Sasha Levin Subject: [PATCH 4.4 12/84] ntp: Allow TAI-UTC offset to be set to zero Date: Thu, 20 Jun 2019 19:56:09 +0200 Message-Id: <20190620174339.252672771@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190620174337.538228162@linuxfoundation.org> References: <20190620174337.538228162@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit fdc6bae940ee9eb869e493990540098b8c0fd6ab ] The ADJ_TAI adjtimex mode sets the TAI-UTC offset of the system clock. It is typically set by NTP/PTP implementations and it is automatically updated by the kernel on leap seconds. The initial value is zero (which applications may interpret as unknown), but this value cannot be set by adjtimex. This limitation seems to go back to the original "nanokernel" implementation by David Mills. Change the ADJ_TAI check to accept zero as a valid TAI-UTC offset in order to allow setting it back to the initial value. Fixes: 153b5d054ac2 ("ntp: support for TAI") Suggested-by: Ondrej Mosnacek Signed-off-by: Miroslav Lichvar Signed-off-by: Thomas Gleixner Cc: John Stultz Cc: Richard Cochran Cc: Prarit Bhargava Link: https://lkml.kernel.org/r/20190417084833.7401-1-mlichvar@redhat.com Signed-off-by: Sasha Levin --- kernel/time/ntp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index ab861771e37f..0e0dc5d89911 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -633,7 +633,7 @@ static inline void process_adjtimex_modes(struct timex *txc, time_constant = max(time_constant, 0l); } - if (txc->modes & ADJ_TAI && txc->constant > 0) + if (txc->modes & ADJ_TAI && txc->constant >= 0) *time_tai = txc->constant; if (txc->modes & ADJ_OFFSET) -- 2.20.1