Re: wm0 Driver

[Eric Haszlakiewicz <erh%nimenees.com@localhost>]

On Sun, Sep 14, 2008 at 08:50:57PM +0200, Havard Eidnes wrote:
> > Now, each of these machines has at least 1 Intel PRO/1000 multimode
> > fiber network card.  Guess what?  When I try to enable one of them, I
> > get 'fatal page fault in supervisor mode'. Additional statements are
> > 'trap type 6 code 0 eip c05ff9bb cs 8 eflags 10286 cr 2 0 ilevel 6'
> > 'kernel: supervisor trap page fault, code=0'
> > 'Stopped in pid 1368.1 (ifconfig) at netbsd:wm_tbi_mediachange+0xb 
> > movl 0(%eax),%esi'
> 
> Disassembly of the first part of wm_tbi_mediachange follows(0xb
> is 11):
> 
> (gdb) x/20i wm_tbi_mediachange
> 0x6c0 <wm_tbi_mediachange>:     push   %ebp
> 0x6c1 <wm_tbi_mediachange+1>:   mov    %esp,%ebp
> 0x6c3 <wm_tbi_mediachange+3>:   push   %esi
> 0x6c4 <wm_tbi_mediachange+4>:   push   %ebx
> 0x6c5 <wm_tbi_mediachange+5>:   sub    $0x10,%esp
> 0x6c8 <wm_tbi_mediachange+8>:   mov    0x8(%ebp),%eax
> 0x6cb <wm_tbi_mediachange+11>:  mov    (%eax),%esi
> 0x6cd <wm_tbi_mediachange+13>:  mov    0x26c(%esi),%ebx
> 
> This is early in wm_tbi_mediachange(), which starts with:
> 
> static int 
> wm_tbi_mediachange(struct ifnet *ifp)
> {        
>         struct wm_softc *sc = ifp->if_softc;
>         struct ifmedia_entry *ife = sc->sc_mii.mii_media.ifm_cur;
>         uint32_t status;
>         int i;
> 
> I'm guessing ifp is null.  How that can be I don't know, though.
> You could try setting ddb.commandonenter to "trace" using sysctl,
> perhaps, and thereby gather some more info (if you can't follow
> up on the serial console idea).

Actually, 0xb looks like it's the second line: it's the second memory
op in the disassembled code, and it has no offset which matches up
with if_softc being the first field in the structure.  So, I'm guessing
it's ifp->if_softc that is null.

eric