XPT_GDEVLIST in xpt_action_default has two early-return paths (list
changed and index not found) that set cgdl->status but not ccb_h.status.
Since xpt_action sets ccb_h.status to CAM_REQ_INPROG before dispatching,
and XPT_GDEVLIST is an non-queued CCB, cam_periph_ccbwait skips the
sleep loop and immediately hits the KASSERT checking that status !=
CAM_REQ_INPROG, causing a panic.

Set ccb_h.status = CAM_REQ_CMP at the top of the code rather than the
bottom. Any future error paths will be right (since this command can't
fail at the command level, just in the status of the data level).

PR: 293899
Assisted-By: Claude Opus 4.6 (1M context)
Sponsored by: Netflix