From owner-freebsd-current Thu May 16 0:27:12 2002 Delivered-To: freebsd-current@freebsd.org Received: from tone.orchestra.cse.unsw.EDU.AU (tone.orchestra.cse.unsw.EDU.AU [129.94.242.28]) by hub.freebsd.org (Postfix) with SMTP id 0D93737B403; Thu, 16 May 2002 00:27:02 -0700 (PDT) Received: From mozart With LocalMail ; Thu, 16 May 2002 17:26:32 +1000 From: Cristan Szmajda To: Giorgos Keramidas Date: Thu, 16 May 2002 17:26:32 +1000 (EST) Cc: current@FreeBSD.ORG Subject: Re: bad tcp cksum fffe! In-Reply-To: <20020514173036.GF5715@hades.hell.gr> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Dear Giorgos, Thanks for your suggestion! The problem has gone away by backing off to -O1 in kernel and -O2 in userland. Strange, because I have been using -O3 -fomit-frame-pointer for a while now (/usr/share/examples/etc/make.conf notwithstanding) with ill effects. My bad. Sorry, but I can't be more specific on which particular flag or which particular CVS update caused the problem. CPU too slow. Thanks again, -- Chris On Tuesday, Giorgos Keramidas said: > On 2002-05-14 17:39, Cristan Szmajda wrote: > > Dear freebsd-current, > > > > Any suggestions you have regarding this problem would be > > much appreciated. > > > > My laptop running -CURRENT is suddenly generating bad TCP > > checksums when talking to some IPs but not others. For > > example, 129.94.209.220 is a problem, > > > > 17:08:47.026823 129.94.233.200.1032 > 129.94.209.220.22: S > > [bad tcp cksum fffe!] 3868790363:3868790363(0) win 65535 > > > > (DF) (ttl 64, id 347, len 68) > > I've seen this only twice. The first time I was using too funky > optimizations to the CFLAGS of my kernel, and GCC was obviously doing > something wrong with the checksum generation code. If this is the > case, then rebuild your kernel and userland with the suggested > optimizations from /usr/share/examples/etc/make.conf and see if this > fixes things for you. > > The second one was when my tcpdump (and the rest of the userland) was > really VERY out of sync with the running kernel (I had managed to > upgrade only the kernel and tcpdump was probably reading random data > from bpf). But there were other more important things wrong with this > case. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message