netdev - Re: Linux 3.6.x kernel crash in tcp_slow_start / bictcp_cong

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Message-ID: <20130124071407.GH8912@reaktio.net>
Date:	Thu, 24 Jan 2013 09:14:07 +0200
From:	Pasi Kärkkäinen <pasik@....fi>
To:	netdev@...r.kernel.org
Subject: Re: Linux 3.6.x kernel crash in tcp_slow_start / bictcp_cong_avoid
 with wfica

On Wed, Jan 23, 2013 at 11:00:39PM +0100, Hannes Frederic Sowa wrote:
> On Wed, Jan 23, 2013 at 11:51:51PM +0200, Pasi Kärkkäinen wrote:
> > On Wed, Jan 23, 2013 at 10:44:45PM +0100, Hannes Frederic Sowa wrote:
> > > On Wed, Jan 23, 2013 at 06:12:38PM +0200, Pasi Kärkkäinen wrote:
> > > > My laptop running Fedora 17 randomly crashes when using wfica (Citrix Receiver / ICA Client) 
> > > > proprietary closed source client for accessing remote desktop server. 
> > > > wfica is running as a normal user, so it shouldn't be able to cause a kernel crash. 
> > > > 
> > > > Crashes seem to happen most often when I use either wlan- or 3G mobile data Internet connection. 
> > > > These kernel crashes happen ramdomly, often 1-2 times a week. 
> > > > What usually happens is that I notice the Internet connection has died, 
> > > > and when I check the kernel dmesg I'm seeing the traceback. 
> > > > At this point I'm still able to use the gnome desktop for maybe 1-5 minutes, 
> > > > but applications start to fail one by one, and finally everything just halts 
> > > > and I need to power cycle the laptop. 
> > > 
> > > Would it be possible to capture a strace -e network, so we could see which
> > > setsockopt combinations are being applied to the socket. Is capturing ss -ioem
> > > in such moments still possible?
> > > 
> > 
> > I don't think I'm able to strace or anything at that point.. 
> > It took me at least 10 tries (=crashes) before I was able to "dmesg > log.txt" successfully .. 
> > (usually writing/redirecting to a file fails because the disk/fs is already unavailable..)
> 
> The strace can be done without the system going downhill. Instead of
> -e network, "-e socket,connect,setsockopt,getsockopt,shutdown,close"
> can be used to reduce the output.
>

Ok, attached is the output of:
strace -e socket,connect,setsockopt,getsockopt,shutdown,close /opt/Citrix/ICAClient/wfica Downloads/launch.ica > wfica-strace.txt 2>&1

That was only a short session, maybe 2 minutes. No problems/crash during that session.

Thanks,

-- Pasi


View attachment "wfica-strace.txt" of type "text/plain" (169467 bytes)