Re: (ITS#7249) slapd segfault with memberof overlay on frontend db

[jvcelak@redhat.com]

> What happens is that the memberof overlay, when stacked on the frontend
> database, keeps looping until the stack is exhausted, since internal
> modifications keep calling the frontend's modify hook rather than the
> actual one that needs to be called.

I have no idea how to fix it. I probably do not understand the manipulation 
with BackedInfo structures fully.

It is obious that it is caused by doing a search from the modrdn operation 
callback memberof_res_modrdn() which is set up in memberof_op_modrdn(). Other 
backends does not call any backend operation at the same moment (op->callback).

Frontend fe_op_search() is called. It tries to choose the right backend with 
select_backend(). Which returns the overlay backend (bi_type == "over"), 
over_op_walk() then selects fe_op_search() again, and we are looping infinitely.

I have no clue how to hide or temporarily deactivate the overlay in 
memberof_res_modrdn() to make the select_backend() function to choose the right 
underlaying backend. Or maybe I have choosen a wrong way of fixing it.

All ideas are welcomed. :-)

Thanks & Regards,

Jan