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=-8.7 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=ham 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 387B3C31E45 for ; Thu, 13 Jun 2019 16:04:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11DFB206E0 for ; Thu, 13 Jun 2019 16:04:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560441867; bh=LoeZwMdx8lyEmitXs28F03cf04OY7TJPSfs/FF3NIJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=I+92Ujbb237q21CDoygjvp+/8R+yFkty/bwGDgqVlQ0eOWc5t6J+/j7y1ydniEhGg sgdfNY/NMECwan8keNdV/Sq0MoPO1Bscc1FHDhiaDi+ZZwXWcdNkAPnPcyfpz/INzs 5K+99rs/ToJ3ik9SOb3JdLC9vfGse+LDDCayk0Yg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391165AbfFMQE0 (ORCPT ); Thu, 13 Jun 2019 12:04:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:35328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731354AbfFMIq7 (ORCPT ); Thu, 13 Jun 2019 04:46:59 -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 C274521743; Thu, 13 Jun 2019 08:46:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560415618; bh=LoeZwMdx8lyEmitXs28F03cf04OY7TJPSfs/FF3NIJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M7On0Ekx01vB7MHDpYcohNVHU9IkEVUp4gld2sSQt+bsCWM7UcIig7eltuhnrmIsE OvhzlqkCLt+zxEJ7leKERqD+jBDu/Ccobu+3qY/rFTEgSA6JchCENp1LbAdie7OrOq k6oGdsM0Ld54umCSUq6eGn0iLZT+LT1rfcdkqNRc= 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 5.1 041/155] ntp: Allow TAI-UTC offset to be set to zero Date: Thu, 13 Jun 2019 10:32:33 +0200 Message-Id: <20190613075655.401187746@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190613075652.691765927@linuxfoundation.org> References: <20190613075652.691765927@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 92a90014a925..f43d47c8c3b6 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -690,7 +690,7 @@ static inline void process_adjtimex_modes(const struct __kernel_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