On Fri, Jan 10, 2014 at 09:37:33AM +0100, Fabien Thomas wrote: > > Le 10 janv. 2014 ? 02:21, Yonghyeon PYUN <pyu...@gmail.com> a ?crit : > > > On Thu, Jan 09, 2014 at 04:06:09PM +0100, Alexandre Martins wrote: > >> Dear, > >> > >> I experience some troubles with the igb device driver on FreeBSD 10-RC4. > >> > >> The kernel make a pagefault in the igb_tx_ctx_setup function when > >> accessing to > >> a IPv6 header. > >> > >> The network configuration is the following: > >> - box acting as an IPv6 router > >> - one interface with an IPv6 (igb0) > >> - another interface with a vlan, and IPv6 on it (vlan0 on igb1) > >> > >> Vlan Hardware tagging is set on both interfaces. > >> > >> The packet that cause the crash come from igb0 and go to vlan0. > >> > >> After investigation, i see that the mbuf is split in two. The first one > >> carry > >> the ethernet header, the second, the IPv6 header and data payload. > >> > >> The split is due to the "m_copy" done in ip6_forward, that make the mbuf > >> not > >> writable and the "M_PREPEND" in ether_output that insert the new mbuf > >> before > >> the original one. > >> > >> The kernel crashes only if the newly allocated mbuf is at the end of a > >> memory > >> page, and no page is available after this one. So, it's extremly rare. > >> > >> I inserted a "KASSERT" into the function (see attached patch) to check > >> this > >> behavior, and it raises on every IPv6 forwarded packet to the vlan. The > >> problem disapear if i remove hardware tagging. > >> > >> In the commit 256200, i see that pullups has been removed. May it be > >> related ? > >> > > > > I think I introduced the header parsing code to meet controller > > requirement in em(4) and Jack borrowed that code in the past but it > > seems it was removed in r256200. It seems igb_tx_ctx_setup() > > assumes it can access ethernet/IP/TCP/UDP headers in the first mbuf > > of the chain. > > This looks wrong to me. > > Instead of patching each driver with pullup code we can add a generic pullup > code ? > - get the contiguous protocol requirement (L2, L3, L4) from underlying driver. > - do the pullup >
I believe Andre already planned that and he would be working on removing home-grown header parser implemented in drivers. > > > >> Can you confirm the problem ? > >> > > > > Probably Jack can tell more about change made in r256200. It's not > > easy for me to verify correctness of igb(4) at this moment. > > > >> Best regards > >> > >> -- > >> Alexandre Martins > >> NETASQ -- We secure IT > _______________________________________________ firstname.lastname@example.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"