From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ralf Baechle DL5RB Subject: Re: AX25 patches and how it affects the end user Date: Wed, 18 Jan 2006 21:52:29 +0000 Message-ID: <20060118215229.GA3337@linux-mips.org> References: <9923fd660601110945p4c4ce12aw3311ae7e55111df1@mail.gmail.com> <000d01c616fc$5624f4b0$3849a8c0@lan.w1nr.net> <20060113210925.GB3516@linux-mips.org> <43CD2275.8050602@ccr.jussieu.fr> <20060118010843.GA3312@linux-mips.org> <620c90570601180426h7ae0a44dv785f2f961b894f20@mail.gmail.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <620c90570601180426h7ae0a44dv785f2f961b894f20@mail.gmail.com> Sender: linux-hams-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Chuck Hast Cc: Bernard Pidoux , "Mike McCarthy, W1NR" , Douglas Cole , linux-hams@vger.kernel.org On Wed, Jan 18, 2006 at 07:26:45AM -0500, Chuck Hast wrote: > > > After applying mkiss patch to kernel 2.6.15.1 I compiled it for a 3 GHz > > > Xeon P4 configuring it for SMP and multithread plus lock options. > > > > > > The SMP kernel seems very sensitive to AX25 configuration errors and it > > > locks up quite soon in that case when loading applications. > > > > > > However when ax25 is carefully initialized, mkiss, kissattach, ax25ipd > > > and ROSE/FPAC switch software suite) are running without problem. > > > > > > But there is still a spinlock lockup when shutting down the system. > > > > > > Here is a copy of the sequence I made by hand (subject to errors) : > > > > Thanks. Btw, in some cases digital cameras have served well to catch > > messages from screens without types - just make sure the images aren't > > larger than necessary to be readable. > > > > > Spinlock lockup on CPU#0, kissattach / 5048, f8d68714 > > > EIP > > > rose_remove_neigh + 0x30/0xb0 [rose] > > > rose_rt_device_down + 0xeb / 0x120 [rose] > > > rose_device_event + 0x42/0x50 [rose] > > > notifier_call_chain + 0x2/0x50 [rose] > > > dev_close + 0x7b/0xb0 > > > unregister_netdevice + 0x19e/0x250 > > > unregister_netdev+0x16/0x1d > > > mkiss_close + 0x4a /0xa0 [mkiss] > > > release_dev.... > > > tty_release ... > > > > > > Hope this can help. > > > Please suggest any more test to be done. > > > > I think the ROSE routing code is beyond recovery. The current data > > structures requires extensive locking code that is easily prone to > > deadlocks like this. It also is slow - fortunately nobody is using ROSE > > on highspeed links ... > > > > Anyway, the problem is pretty obvious in your traceback and I'll cook a > > patch for you to test. > > > > What do you consider high speed links? We will be doing so in Florida > as we move the switches around the state to Linux. Some of these devices > will be linked over 802.11 type links. That certainly would be a fast link. There are not only the limits of the code itself but also the design limits of the connected mode protocols themselves which become a theoretical limit for what is possible with AX.25. Ralf