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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 0F50BC432C0 for ; Fri, 22 Nov 2019 05:58:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7DF92070A for ; Fri, 22 Nov 2019 05:58:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574402323; bh=em/d8aYF1bMtjXSLVU4kj2JcBOP0Eed2tRCO1S+7JDg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dul0pA6/I0ITdekcuUTPwfsXD4nE6L9wF/FNwPJSgcjyCXl33LMUGy6KUmNRWY/tr LgtWq4cb21nD1WnHxROiin0E7/AtbdVy/Ka6oDZ1nXYNUJfFgbWxNULDIIGcu9tHqX 1eBqLZSdDSjQs+4xCPwAmK3+6JkX092EUFEPRXZc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729618AbfKVF6G (ORCPT ); Fri, 22 Nov 2019 00:58:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:36476 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728359AbfKVF5z (ORCPT ); Fri, 22 Nov 2019 00:57:55 -0500 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 1EAFC2089D; Fri, 22 Nov 2019 05:57:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574402274; bh=em/d8aYF1bMtjXSLVU4kj2JcBOP0Eed2tRCO1S+7JDg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r7msxJzlvyDQk4mtKxo/R51Ts9MnYFG+RHstLhfZA3bTrQdZcPvHyIm+dQIOmEHIC R36dFXJVgCSPEDVcFz+mjhLdYCAh1TqgeOSaN2axnsR8M2p2INT5kmCOWcKiW3GGq1 4QULPu64n6UuL/bxMR56eigqEni4AR8kJPRyQsr0= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Maciej Kwiecien , Marcin Stojek , Alexander Sverdlin , Marcelo Ricardo Leitner , "David S . Miller" , Sasha Levin , linux-sctp@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 113/127] sctp: don't compare hb_timer expire date before starting it Date: Fri, 22 Nov 2019 00:55:31 -0500 Message-Id: <20191122055544.3299-112-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191122055544.3299-1-sashal@kernel.org> References: <20191122055544.3299-1-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: 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 43105cf04bc45..274df899e7bfa 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -210,7 +210,8 @@ 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