MPSAFE fxp m_pkthdr not valid

[Andrew Gallatin]

Nate Lawson writes:
 > I have gotten fxp running with MPSAFE and did a large scp transfer.  It
 > ran for a few minutes and then paniced.  It was trap 12 (page fault) at
 > address 0x24.  Here is where it crashed:
 > 
<..>
 > The deref of mb_head->m_pkthdr is invalid.  Note that my fxp_intr function
 > acquires the fxp lock right away so this shouldn't be a race in fxp.

Where else is the lock acquired?  It would be easier to help if we
could see a diff..

Drew