BIRD crashing when --enable-debug is set

[Toke Høiland-Jørgensen]

Maria Matějka <maria.matejka at nic.cz> writes:

> Hello!
>
> Just a quick reply from my phone. When adding these checks, I also
> wanted to zero out slab objects but then I realized that these objects
> should be initialized anyway after allocation and in most cases all of
> these would be rewritten twice.
>
> The preferred way of using slab objects is therefore a full init by
> structure assignment after alloc like this:
>
> struct foo *f = sl_alloc(...);
> *f = (struct foo) {...};
>
> In cases of other allocations, there are allocz variants to zero the
> allocated memory instead of having to call memset, yet slabs are
> intended to be a fixed-size structure allocator which corresponds to a
> possibility of direct structure assignment.
>
> I hope this is sufficient explanation. Feel free to dispute it or
> discuss anyway, I may be wrong somehow.

Well, that's certainly not what the Babel code is doing :)

I'm not a huge fan of the struct assignment to pointers thing (there's
the thing where it doesn't zero out padding, but mostly I just think
it's ugly :)). However, I do see it is widely used in the Bird codebase,
now that you mention it. And it's not a hugely invasive patch to fix the
Babel code to use it, so if you prefer that I can send such a patch...

-Toke