Date: Sat, 22 Aug 2015 08:11:04 -0400 (EDT) From: Rick Macklem <rmacklem@uoguelph.ca> To: Joel Dahl <joel@vnode.se> Cc: current@freebsd.org Subject: Re: Kernel panic with fresh current, probably nfs related Message-ID: <364980918.28933112.1440245464236.JavaMail.zimbra@uoguelph.ca> In-Reply-To: <20150822115519.GA79434@ymer.vnode.se> References: <20150822115519.GA79434@ymer.vnode.se>
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------=_Part_28933110_1479675019.1440245464233 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Joel Dahl wrote: > Hi, > > I hit a kernel panic running a fresh -CURRENT today. This machine is my home > NFS > server and it exports src and obj to a bunch of other machines. During an > installkernel on one of the other machines (using the src and obj exports > from > the NFS server) the NFS server kernel paniced. > > I took a quick photo of the stack backtrace, since I didn't have time to > investigate further (but I haven't rebooted the machine yet, it's still > sitting at the db> prompt: > > http://mirror.vnode.se/upload/panic001-20150822.JPG > > Any ideas? The panic is "tcp_output: len > IP_MAXPACKET". This would be a TCP/TSO problem and not NFS. NFS just puts stuff on the TCP socket for transmission through the kernel rpc layer. (It happens to do so in a way that the TSO code gets tested in ways that a netperf test won't do.) Take a look at the net device driver for your hardware and see if if_hw_tsomax is set to > IP_MAXPACKET somehow. If it is, the value needs to be changed to IP_MAXPACKET or less. You can also try the attached patch for a related issue for net drivers that can't handle 35 transmit segments for a TSO segment, although this shouldn't problem wouldn't cause the above panic unless if_hw_tsomax wasn't set correctly, from what I can see looking at the code. If you just want to make the panic go away "disable TSO", but it would be nice if we knew what net driver you were using and how this was caused? rick > > -- > Joel > _______________________________________________ > freebsd-current@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" > ------=_Part_28933110_1479675019.1440245464233 Content-Type: text/x-patch; name=tsooutby1.patch Content-Disposition: attachment; filename=tsooutby1.patch Content-Transfer-Encoding: base64 LS0tIG5ldGluZXQvdGNwX291dHB1dC5jLnNhdgkyMDE1LTA4LTIyIDA3OjQ4OjEyLjAwMDAwMDAw MCAtMDQwMAorKysgbmV0aW5ldC90Y3Bfb3V0cHV0LmMJMjAxNS0wOC0yMiAwNzo1MDo1Mi4wMDAw MDAwMDAgLTA0MDAKQEAgLTc5NCw3ICs3OTQsMTMgQEAgc2VuZDoKIAogCQkJLyogZXh0cmFjdCBU U08gaW5mb3JtYXRpb24gKi8KIAkJCWlmX2h3X3Rzb21heCA9IHRwLT50X3Rzb21heDsKLQkJCWlm X2h3X3Rzb21heHNlZ2NvdW50ID0gdHAtPnRfdHNvbWF4c2VnY291bnQ7CisJCQkvKgorCQkJICog U3VidHJhY3QgMSBmb3IgdGhlIHRjcC9pcCBoZWFkZXIgbWJ1ZiB0aGF0CisJCQkgKiB3aWxsIGJl IHByZXBlbmRlZCB0byB0aGlzIG1idWYgY2hhaW4gYWZ0ZXIKKwkJCSAqIHRoZSBjb2RlIGluIHRo aXMgc2VjdGlvbiBsaW1pdHMgdGhlIG51bWJlciBvZgorCQkJICogbWJ1ZnMgaW4gdGhlIGNoYWlu IHRvIGlmX2h3X3Rzb21heHNlZ2NvdW50LgorCQkJICovCisJCQlpZl9od190c29tYXhzZWdjb3Vu dCA9IHRwLT50X3Rzb21heHNlZ2NvdW50IC0gMTsKIAkJCWlmX2h3X3Rzb21heHNlZ3NpemUgPSB0 cC0+dF90c29tYXhzZWdzaXplOwogCiAJCQkvKgo= ------=_Part_28933110_1479675019.1440245464233--
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