From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: Fw: [Bug 199995] New: Ramdomly sent TCP Reset from Kernel with bonding mode "brodcast" Date: Fri, 8 Jun 2018 14:53:22 -0700 Message-ID: References: <20180608095954.4a0437e4@xeon-e3> <20180608210403.2moomjshtwszvsso@unicorn.suse.cz> <3cbd2c1f-4e03-1cb1-3731-4ce440778bb8@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Eric Dumazet , Michal Kubecek , Stephen Hemminger Return-path: Received: from mail-pf0-f170.google.com ([209.85.192.170]:42628 "EHLO mail-pf0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752923AbeFHVxZ (ORCPT ); Fri, 8 Jun 2018 17:53:25 -0400 Received: by mail-pf0-f170.google.com with SMTP id w7-v6so7256264pfn.9 for ; Fri, 08 Jun 2018 14:53:25 -0700 (PDT) In-Reply-To: <3cbd2c1f-4e03-1cb1-3731-4ce440778bb8@gmail.com> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 06/08/2018 02:38 PM, Eric Dumazet wrote: > > > On 06/08/2018 02:04 PM, Michal Kubecek wrote: >> >> However, the lockless listener was introduced in 4.4 so it's not clear >> why reporter started encountering this after an upgrade from 4.13 to >> 4.15. > > Yes, I do not buy this at all. > > If two identical SYN are received by two cpus, we should create one SYN_RECV and send > two SYNACK. > > But it is a bit hard to test this :/ > > I will take a look, thanks. Oh well, this is not done as I thought, this needs a fix, I will work on this. reqsk_queue_hash_req() calls inet_ehash_insert() without making sure that the same 4-tuple is not already there. Do not worry, we will keep the listener lockless :)