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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,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 DCA66C28CC1 for ; Sat, 1 Jun 2019 13:23:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4B4C2735D for ; Sat, 1 Jun 2019 13:23:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559395396; bh=zrtdq2BIE9jOKb2LdQMn8+1cTfS9+Ij+vtD4sbtBBSw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=djr3n2k9viOSAhn6gqW8n+yfno4TDr7O2XsWIsdQkdTNoYH0rS8P1zBkeiQBWhnPv sjVanhFDZFSL+G+5Bx00gYhFtOSbLivciIyzJ+bQKg7dt4mfrJGhPZ1Jd6q40sgfsL ejT4RN2x96DYGohfYdHx6/ex+t5IIqSEEVDNc9h4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728948AbfFANXQ (ORCPT ); Sat, 1 Jun 2019 09:23:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:52952 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728893AbfFANXN (ORCPT ); Sat, 1 Jun 2019 09:23:13 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D9A0327359; Sat, 1 Jun 2019 13:23:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559395392; bh=zrtdq2BIE9jOKb2LdQMn8+1cTfS9+Ij+vtD4sbtBBSw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F+6zeeaNbwJ5I6/QclvfE9yWskYESZ+fh67G7hpONuTLRE3/O8BnFiCZb6uEJmPGc 2Ha9/3jUE5kR/KjZevrdm5mXk5IXI20gJDg5Do54+M+y/A2807vBvsthPnbRPxkbE3 M16w8oeY1mm6v9uRjdHI/Ewx5VdyAFhxdTS79A84= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Miroslav Lichvar , Ondrej Mosnacek , Thomas Gleixner , John Stultz , Richard Cochran , Prarit Bhargava , Sasha Levin Subject: [PATCH AUTOSEL 4.19 033/141] ntp: Allow TAI-UTC offset to be set to zero Date: Sat, 1 Jun 2019 09:20:09 -0400 Message-Id: <20190601132158.25821-33-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190601132158.25821-1-sashal@kernel.org> References: <20190601132158.25821-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Miroslav Lichvar [ 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 c5e0cba3b39cc..6b23cd584295f 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -698,7 +698,7 @@ static inline void process_adjtimex_modes(const struct timex *txc, s32 *time_tai 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