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 D2900C43613 for ; Thu, 20 Jun 2019 18:29:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEAC120665 for ; Thu, 20 Jun 2019 18:29:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561055358; bh=JZ3Sjdss1HKHu3kqC2+Tjm0+Kqd12auZY9kdtctNI5Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qmKu4uh+gfgYf/sRqPN+Hq6u+FowfyeMyIntwKz8JRSFN4AebptTDZXnVO0IKeH+J HlTg7U/JDccNwDvTa1kKLGl7hN8py6qS72TUQwambnq0VF2nGWt+XM3VDecXTVbZgi 8idmyFdguUYsRtROu+81AJNrHbQvwJmw5NtxjksU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727502AbfFTSCs (ORCPT ); Thu, 20 Jun 2019 14:02:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:53654 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727497AbfFTSCs (ORCPT ); Thu, 20 Jun 2019 14:02:48 -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 68F4F204FD; Thu, 20 Jun 2019 18:02:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561053766; bh=JZ3Sjdss1HKHu3kqC2+Tjm0+Kqd12auZY9kdtctNI5Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Za6B3p7PviTDlsIhPUOMFSuoal3bATuYq+egV2CN2XIqjzPs6JHOYonwP5qYJd5Fm Z/4BeoMOy0jCXmWWFHwu3oRV1DJCHDeeQ61LF3etQyXQ+Pb9XswqGys5Onv0zh0Lz9 uQmFWiPeS3nkkjZo9ab8PO2/wlS3sn1LyOQeV/eg= 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 4.9 020/117] ntp: Allow TAI-UTC offset to be set to zero Date: Thu, 20 Jun 2019 19:55:54 +0200 Message-Id: <20190620174353.195845817@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190620174351.964339809@linuxfoundation.org> References: <20190620174351.964339809@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 6df8927c58a5..0a16419006f3 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -639,7 +639,7 @@ 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