Re: Trap 0x34 panic on 5.1 on Blade 100

[George Harvey <fr30%dial.pipex.com@localhost>]

On Thu, 12 May 2011 18:15:30 +0000 (UTC)
Eduardo Horvath <eeh%NetBSD.org@localhost> wrote:

> On Thu, 12 May 2011, George Harvey wrote:
> > 
> > After further testing, it appears that I only get panics when using the
> > on-board gem interface with a 100Mb half-duplex connection.
> > Specifically, when connected to a 3Com SuperStack II Dual Speed Hub 500.
> > With a full-duplex switch connection, or even with an old 10Mb hub, I
> > don't get any panics. The following backtrace is from a panic caused
> > by starting xterm over ssh. FTP and NFS also produce similar panics:
> > 
> > blade100# trap type 0x34: cpu 0, pc=137b108 npc=137b10c 
> > pstate=44800006<PRIV,IE> kernel trap 34: mem address not aligned
> > Stopped in pid 451.1 (sshd) at  netbsd:m_xhalf+0x8:
> >  ld [%o0 + 0 x20], %g2
> > db> bt
> > bpf_mtap(2ed0e00, c78c0f0, 0, 800, 2, 0) at netbsd:bpf_mtap+0xd4
> > gem_rint(c78c000, 80000000, 17d8, 1ff00400000, 4, 4000) at
> > netbsd:gem_rint+0x2cc
> 
> Hm.  Are you using the packer filter?  Looks like it's not accessing 
> unaligned data properly.  Lessee... best to get a full disassembly of the 
> function, but assuming %o0 didn't change the signature is 
> m_xhalf(const struct mbuf *m, uint32_t k, int *err)
> so it's trying to load something 32-bytes into the mbuf.

I haven't configured any packet filters but I am using dhclient and
dhclient uses bpf. As a test, I disabled dhclient, set a static IP
address, and found that the panics stop. Instead I see network
errors like this:

gem0: discarding oversize frame (len=6330)
gem0: receive error: CRC error
gem0: discarding oversize frame (len=6330)
gem0: discarding oversize frame (len=6330)
gem0: receive error: CRC error

The oversize frame messages may be bogus, the hub has an RMON agent and
that reports collisions and fragments but no oversize packets.

George