From owner-freebsd-stable@freebsd.org Mon Oct 10 13:32:24 2016 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 3F092C0BFD6 for ; Mon, 10 Oct 2016 13:32:24 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id F1131C08; Mon, 10 Oct 2016 13:32:23 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from slw by zxy.spb.ru with local (Exim 4.86 (FreeBSD)) (envelope-from ) id 1btagm-000AdC-Dh; Mon, 10 Oct 2016 16:32:20 +0300 Date: Mon, 10 Oct 2016 16:32:20 +0300 From: Slawa Olhovchenkov To: Julien Charbon Cc: Konstantin Belousov , freebsd-stable@FreeBSD.org, hiren panchasara Subject: Re: 11.0 stuck on high network load Message-ID: <20161010133220.GU54003@zxy.spb.ru> References: <20160923200143.GG2840@zxy.spb.ru> <20160925124626.GI2840@zxy.spb.ru> <20160926172159.GA54003@zxy.spb.ru> <62453d9c-b1e4-1129-70ff-654dacea37f9@gmail.com> <20160928115909.GC54003@zxy.spb.ru> <20161006111043.GH54003@zxy.spb.ru> <1431484c-c00e-24c5-bd76-714be8ae5ed5@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1431484c-c00e-24c5-bd76-714be8ae5ed5@freebsd.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: slw@zxy.spb.ru X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 10 Oct 2016 13:32:24 -0000 On Mon, Oct 10, 2016 at 01:26:12PM +0200, Julien Charbon wrote: > > Hi, > > On 10/6/16 1:10 PM, Slawa Olhovchenkov wrote: > > On Thu, Oct 06, 2016 at 09:28:06AM +0200, Julien Charbon wrote: > > > >> 2. thread1: In tcp_close() the inp is marked with INP_DROPPED flag, the > >> process continues and calls INP_WUNLOCK() here: > >> > >> https://github.com/freebsd/freebsd/blob/releng/11.0/sys/netinet/tcp_subr.c#L1568 > > > > Look also to sys/netinet/tcp_timewait.c:488 > > > > And check other locks from r160549 > > You are right, and here the a fix proposal for this issue: > > Fix a double-free when an inp transitions to INP_TIMEWAIT state after > having been dropped > https://reviews.freebsd.org/D8211 > > It basically enforces in_pcbdrop() logic in tcp_input(): A INP_DROPPED > inpcb should never be proceed further. > > Slawa, as you are the only one to reproduce this issue currently, could > test this patch? (And remove the temporary patch I did provided to you > before). > > I will wait for your tests results before pushing further. > > Thanks! > > diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c > index c72f01f..37f27e0 100644 > --- a/sys/netinet/tcp_input.c > +++ b/sys/netinet/tcp_input.c > @@ -921,6 +921,16 @@ findpcb: > goto dropwithreset; > } > INP_WLOCK_ASSERT(inp); > + /* > + * While waiting for inp lock during the lookup, another thread > + * can have droppedt the inpcb, in which case we need to loop back > + * and try to find a new inpcb to deliver to. > + */ > + if (inp->inp_flags & INP_DROPPED) { > + INP_WUNLOCK(inp); > + inp = NULL; > + goto findpcb; Are you sure about this goto? Can this cause infinite loop by found same inpcb? May be drop packet is more correct?