Manuel Bouyer <bouyer@antioche.eu.org> typed:
: mishka@ reported a panic in m_makewritable() because of a DEBUG check:
:         error = m_copyback0(mp, off, len, NULL,
:             M_COPYBACK0_PRESERVE|M_COPYBACK0_COW, how);

I saw something similar with it in ipf which has:

    static int fr_check_wrapper(arg, mp, ifp, dir)
    ...
    #if __NetBSD_Version__ >= 200080000
    ...
            int error = m_makewritable(mp, 0, M_COPYALL, M_DONTWAIT);

and causes one of my uses of it to be dysfunctional unless removed (but
removing it supposedly causes panics for other people).
When I looked through it quickly (around a year ago) I couldn't see
anything obviously wrong.  IIRC I had m_copyback0() or maybe
m_makewritable() logging or kprintf-ing on error in there but nothing
showed up.  Someone else want to take a look?

Regards,
Geoff