dtrace discuss - Apr 2009 - Structure bit-field causing Dtrace to throw alignment errors

I''ve got a real simple dtrace script, which I''m having some
issues
with.  The script...


#pragma D option quiet

fbt::ssfcp_transport:entry
{
  this->pkt=(fc_packet_t *) arg1;
  this->frame=this->pkt->pkt_cmd_fhdr;
  printf("%x \n",this->pkt->pkt_cmd_fhdr.d_id);
}

When it is run, I get the following errors...

dtrace: error on enabled probe ID 1 (ID 37303: 
fbt:fcp:ssfcp_transport:entry): invalid alignment (0x6001245a791) in 
action #3 at DIF offset 20

The d_id field is a bit-field, from this structure...

typedef struct frame_header {
 #if defined(_BIT_FIELDS_LTOH)
    uint32_t    d_id    : 24,
            r_ctl    : 8;
     uint32_t    s_id    : 24,
             rsvd    : 8;
     uint32_t    f_ctl    : 24,
             type    : 8;
     uint32_t    seq_cnt    : 16,
             df_ctl    : 8,
             seq_id     : 8;
     uint32_t    rx_id    : 16,
             ox_id    : 16;
     uint32_t    ro;
 
 #else
     uint32_t    r_ctl     : 8,
             d_id     : 24;
     uint32_t    rsvd     : 8,
             s_id    : 24;
     uint32_t    type    : 8,
             f_ctl    : 24;
     uint32_t    seq_id    : 8,
             df_ctl    : 8,
             seq_cnt    : 16;
     uint32_t    ox_id    : 16,
             rx_id    : 16;
    uint32_t    ro;
 #endif    /* _BIT_FIELDS_LTOH */
} fc_frame_hdr_t;

Is there any way to cast these bit-fields, to avoid the errors?

Thanks,
Jim