On 2023-12-05 20:00, Alexander Bluhm wrote:
*cpu0: receive 1: so 0xfffffd80259ea760, so_type 3, sb_cc 40
When the multicast routing daemon reads from raw socket, the kernel
crashes. Kernel has no data in the queue, but counter says there
should be 40 bytes. So it panics.
What kind of multicast traffic are you using mrouted for?
Is the machine stable if you don't start mrouted?
Does it help if you emulate only one virtual CPU?
Well, it was more of a test if i could get upnp stuff routed across
a subnet. I got a few audio boards from chinese origin running and
locked them down in their own subnet. For the app to find it i wanted
to setup multicast routing but never really got it working for these
devices.
For sonos it works however. I can try running on a single cpu, however
maybe its
a good idea to just change 1 thing at the time and first start the
tcpdump as you
asked below?
It could be race or a single packet that crashes the machine. Can
you use tcpdump e.g. on the vm host to see what packets are delivered
to mrouted when the crash happens? It may be an IGMP packet.
Well, since crashes are quite rare I think its going to take some time
to
collect this data. I could start a tcpdump in the background though and
hope for the best.
netstat -na and netstat -g output would be useful. fstat -p <pid
of mrouted> helps to see for which sockets recvfrom(2) may be called.
wait until the kids come complaining internet is not working anymore.
Sorry, no kids around to reproduce. I need your help to debug.
I got 4, can borrow one if you want to help debug.
Other than that, I suspect the issue was introduced in 7.3 because
(iirc) I
never ran into that issue before 7.3.
Kr,
Jo
