On Tue, 4 Sep 2018 20:18:29 +0200 Vincenzo Maffione <v.maffi...@gmail.com> wrote:
> Hi, > I don't think the panic depends on the architecture. Also, it does > not depend on using emulated mode or not. > We have seen this happening on x86_64 on FreeBSD 12 head. > > As John-Mark says, kdloading netmap.ko is not enough. You need to > open a netmap port corresponding > to any network interface, e.g. > # pkt-gen -i eth0 > because this will trigger ifunit_ref() in the kernel (netmap tries to > grab the interface called "eth0"). > The ifunit_ref() panics and we still need to figure out why. After more carefully rereading jmg's original report, on amd64 I reproduced exactly the same panic he reported on arm64, the summary follows: - the problem can be observed as VNET related, and can be triggered only on kernels built with "options VIMAGE" but without "device netmap". - netmap.ko built using make buildkernel works fine. - netmap.ko built separately (cd sys/modules/netmap; make) panics on a first reference to vale interface, such as "tcpdump -ni vale1:a" - the problem is that the separately built module is compiled without "options VIMAGE", and as such does not set curvnet prior to calling into network stack functions, therefore we have a null pointer dereference in ifunit_ref() and voila... - hence, there's nothing to fix in the netmap code, and there's nothing to fix in the network stack either related to this particular problem, but rather we need a general mechanism which would prevent kldloading non-VNETized .ko modules into a VNETized kernel. I have no idea how to approach this, besides adding bz@ to the cc: list, perhaps he could chime in with some thoughts? Cheers, Marko _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
