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=-8.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT 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 4B9E8C43381 for ; Fri, 22 Feb 2019 12:49:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1975E2075C for ; Fri, 22 Feb 2019 12:49:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="cGZQm3ze" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726923AbfBVMtT (ORCPT ); Fri, 22 Feb 2019 07:49:19 -0500 Received: from mail-qt1-f195.google.com ([209.85.160.195]:45981 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726087AbfBVMtS (ORCPT ); Fri, 22 Feb 2019 07:49:18 -0500 Received: by mail-qt1-f195.google.com with SMTP id d18so2225648qtg.12; Fri, 22 Feb 2019 04:49:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=EreoFQ8uqwGFEbok9lMBMOALpLMRlQsWlC5XfVgxx60=; b=cGZQm3zeZrIGEl7PkPOEbVnjx7cWY8lzBABrGlZc/5QXnMTATTrm2HIVZdY6k61jmO sURl0W+BIPGpQGobgpfyrWNroCY+btz+7lCJHQySIaEew7ZsjPZVgruH5B2OO+SJwSg9 8gDPnsdVqt4p6XbdnzVEIFLkoBrpgslL7+exWfOkLz1Zvzq7zLjPUdj0c0sgVAhk4dyw 4XSSxe+udpJgQHMqaR5A9Yl+OeT5kI2U1cSk0pAvzt8WrtvPPGVCG1xS5HPUGYL62cLw b44wuWAHYWd7WAWK6cNXD/+APas6XYyIrVvF6vH27DmJ1MVUgkZLqj0UTzQMd0qWmcRz okaw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=EreoFQ8uqwGFEbok9lMBMOALpLMRlQsWlC5XfVgxx60=; b=o43CnPBlT957S1VEP+FTskBjyKT6vqOn6Nsr661nl9LSLq8N0jpFWCuNZyTY35Zfg0 uU2pFf85MCAWFBfcMm6vxZfUToN1Wy4n+hstewVWGOM6WMBige4+fwyc9NzZLjSknjwm ZcaKBbqDy9nQu144j28zpgTDdezl795K5pcCcCu6WMM32tSEpyVWyXLpn7CCx6NtqkDg PooQEh13gNjbXMLeUZXHIeV0wDR33Fu8ero6QCPq69pxBvnn2/LazfWtTSRie5qqp7au rZXUeYv3Mec2LOVDIufWKY+qWoZdTrk8iYZdtuBe7zf3G5Z53YJKxJL5hq0vg4W4ZtNS RoWA== X-Gm-Message-State: AHQUAub2Ufb6Xv64GdAuFMb/TzJO2deF9wYKhEYHstnCT5ArwawTGHrn 9Wl9TztWhUK/bdEOCBJ48eU= X-Google-Smtp-Source: AHgI3IbLP6UXAVIWUWlXpm/jsH+r8fopDM9LrzdmMFKTsDX2cbhi49vI2Vmik8MnnzgIekDfXVAb4A== X-Received: by 2002:ac8:1655:: with SMTP id x21mr2870653qtk.281.1550839757224; Fri, 22 Feb 2019 04:49:17 -0800 (PST) Received: from localhost.localdomain ([168.194.160.121]) by smtp.gmail.com with ESMTPSA id z126sm819633qkz.8.2019.02.22.04.49.16 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 22 Feb 2019 04:49:16 -0800 (PST) Received: by localhost.localdomain (Postfix, from userid 1000) id D9C49180CC7; Fri, 22 Feb 2019 09:49:13 -0300 (-03) Date: Fri, 22 Feb 2019 09:49:13 -0300 From: Marcelo Ricardo Leitner To: kwiecienmaciek@gmail.com Cc: linux-sctp@vger.kernel.org, netdev@vger.kernel.org, alexander.sverdlin@nokia.com, Maciej Kwiecien Subject: Re: [PATCH] sctp: don't compare hb_timer expire date before starting it Message-ID: <20190222124913.GM10665@localhost.localdomain> References: <20190222084526.8214-1-maciej.kwiecien@nokia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190222084526.8214-1-maciej.kwiecien@nokia.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Feb 22, 2019 at 09:45:26AM +0100, kwiecienmaciek@gmail.com wrote: > From: Maciej Kwiecien > > 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 Acked-by: Marcelo Ricardo Leitner > --- > 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 033696e6f74f..ad158d311ffa 100644 > --- a/net/sctp/transport.c > +++ b/net/sctp/transport.c > @@ -207,7 +207,8 @@ 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); > -- > 2.14.1 >