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=-9.8 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,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 E8D81C43603 for ; Wed, 4 Dec 2019 18:13:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF66220863 for ; Wed, 4 Dec 2019 18:13:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575483215; bh=Ok3I6A0cc8kL/J20hG8eQcCcmH4Ge5h24qRJu31z9wo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EZjuUK/WKq1Rn34axFURnvrlLqrk9gDPWEryseuYbjvsNsikhTuWpnNYSUV1R1CJH r2U1UAEZjPX1Mtwb5SdHUKN4IEL/BubM8uRx+vu3HfiogZZuHwyEFOztpod9mlfW4G j85VVU60vzOOOX0yo+mA6zCVZWnqTRuHvLUd+0ec= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731777AbfLDSNd (ORCPT ); Wed, 4 Dec 2019 13:13:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:42628 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731753AbfLDSN1 (ORCPT ); Wed, 4 Dec 2019 13:13:27 -0500 Received: from localhost (unknown [217.68.49.72]) (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 123EF20674; Wed, 4 Dec 2019 18:13:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575483207; bh=Ok3I6A0cc8kL/J20hG8eQcCcmH4Ge5h24qRJu31z9wo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L6611LUK1b4ghR6PBGkCDcvm0QcwN55GWg+aHUvWHSrG62EwCybAA30barIjVS1Da tPyOfl2GzAwrU7C3tCp9pUWFLKuuVZ98BGths0CMlJrKsSA1VTlEu/w1PYeYPsAdRo vsXGzPUsHHSFrwVSPRgoUOCodVa9JxomPNwgQRKM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marcin Stojek , Maciej Kwiecien , Alexander Sverdlin , Marcelo Ricardo Leitner , "David S. Miller" , Sasha Levin Subject: [PATCH 4.9 097/125] sctp: dont compare hb_timer expire date before starting it Date: Wed, 4 Dec 2019 18:56:42 +0100 Message-Id: <20191204175325.005448999@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191204175308.377746305@linuxfoundation.org> References: <20191204175308.377746305@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 From: Maciej Kwiecien [ Upstream commit d1f20c03f48102e52eb98b8651d129b83134cae4 ] hb_timer might not start at all for a particular transport because its start is conditional. In a result a node is not sending heartbeats. Function sctp_transport_reset_hb_timer has two roles: - initial start of hb_timer for a given transport, - update expire date of hb_timer for a given transport. The function is optimized to update timer's expire only if it is before a new calculated one but this comparison is invalid for a timer which has not yet started. Such a timer has expire == 0 and if a new expire value is bigger than (MAX_JIFFIES / 2 + 2) then "time_before" macro will fail and timer will not start resulting in no heartbeat packets send by the node. This was found when association was initialized within first 5 mins after system boot due to jiffies init value which is near to MAX_JIFFIES. Test kernel version: 4.9.154 (ARCH=arm) hb_timer.expire = 0; //initialized, not started timer new_expire = MAX_JIFFIES / 2 + 2; //or more time_before(hb_timer.expire, new_expire) == false Fixes: ba6f5e33bdbb ("sctp: avoid refreshing heartbeat timer too often") Reported-by: Marcin Stojek Tested-by: Marcin Stojek Signed-off-by: Maciej Kwiecien Reviewed-by: Alexander Sverdlin Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/sctp/transport.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sctp/transport.c b/net/sctp/transport.c index 03d71cd97ec08..5c78942550e97 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -205,7 +205,8 @@ void sctp_transport_reset_hb_timer(struct sctp_transport *transport) /* When a data chunk is sent, reset the heartbeat interval. */ expires = jiffies + sctp_transport_timeout(transport); - if (time_before(transport->hb_timer.expires, expires) && + if ((time_before(transport->hb_timer.expires, expires) || + !timer_pending(&transport->hb_timer)) && !mod_timer(&transport->hb_timer, expires + prandom_u32_max(transport->rto))) sctp_transport_hold(transport); -- 2.20.1