Date: Wed, 5 Sep 2018 12:36:38 +0200 From: Vincenzo Maffione <v.maffione@gmail.com> To: Marko Zec <zec@fer.hr> Cc: Luigi Rizzo <rizzo@iet.unipi.it>, "freebsd-net@freebsd.org" <net@freebsd.org>, bz@freebsd.org Subject: Re: vale and netmap module questions Message-ID: <CA%2B_eA9gxCrJXVFaooD4x491Ksff5=gomwfn0=E0X0_iuupuBHg@mail.gmail.com> In-Reply-To: <20180905104433.08ad13b8@x23> References: <20180901014953.GV45503@funkthat.com> <CA%2B_eA9gH_uzxV_YLBH1XdM-ygPUxXzD_W9_b45jTmeY-t0bQKg@mail.gmail.com> <20180901211123.GZ45503@funkthat.com> <20180904164303.68c43b6e@x23> <20180904162815.GA75530@funkthat.com> <CA%2B_eA9jp2rB0GjojNrbWuQJ3fChpF6U5KPOX-DvEzJDVzOSP4w@mail.gmail.com> <20180905104433.08ad13b8@x23>
next in thread | previous in thread | raw e-mail | index | archive | help
Hi Marko, Thanks a lot for identifying the problem. If I understand correctly, simply adding -D VIMAGE here https://github.com/luigirizzo/netmap/blob/master/sys/modules/netmap/Makefile#L11 would at least mitigate the issue. If you think I'm right I'll just add it. Thanks, Vincenzo Il giorno mer 5 set 2018 alle ore 10:44 Marko Zec <zec@fer.hr> ha scritto: > On Tue, 4 Sep 2018 20:18:29 +0200 > Vincenzo Maffione <v.maffione@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 > -- Vincenzo
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CA%2B_eA9gxCrJXVFaooD4x491Ksff5=gomwfn0=E0X0_iuupuBHg>