Re: [PATCH nft 2/2] segtree: fix decomposition of unclosed intervals containing address prefixes

[Jeremy Sowden <jeremy@azazel.net>]

[-- Attachment #1: Type: text/plain, Size: 1861 bytes --]

On 2022-09-21, at 13:48:27 +0200, Florian Westphal wrote:
> Jeremy Sowden <jeremy@azazel.net> wrote:
> > @@ -619,24 +622,12 @@ void interval_map_decompose(struct expr *set)
> >
> >  	if (!mpz_cmp(i->value, expr_value(low)->value)) {
> >  		expr_free(i);
> > -		i = low;
> > +		compound_expr_add(set, low);
> >  	} else {
> > -		i = range_expr_alloc(&low->location,
> > -				     expr_clone(expr_value(low)), i);
> > -		i = set_elem_expr_alloc(&low->location, i);
> > -		if (low->etype == EXPR_MAPPING) {
> > -			i = mapping_expr_alloc(&i->location, i,
> > -					       expr_clone(low->right));
> > -			interval_expr_copy(i->left, low->left);
> > -		} else {
> > -			interval_expr_copy(i, low);
> > -		}
> > -		i->flags |= EXPR_F_KERNEL;
> > -
> > +		add_interval(set, low, i);
> >  		expr_free(low);
> >  	}
> >
> > -	compound_expr_add(set, i);
>
> This results in a memory leak:
>
> __interceptor_malloc libsanitizer/asan/asan_malloc_linux.cpp:145
> xmalloc src/utils.c:36
> xzalloc src/utils.c:75
> expr_alloc src/expression.c:46
> constant_expr_alloc src/expression.c:420
> interval_map_decompose src/segtree.c:619

I did try running the new shell test under valgrind: lots of noise, not
a lot of signal. :)

> Before, 'i' was assigned to the compund expr, but thats no longer the
> case.

> Does this look good to you?

Yes, LTGM.

> If so, I will sqash this before applying:
>
> diff --git a/src/segtree.c b/src/segtree.c
> --- a/src/segtree.c
> +++ b/src/segtree.c
> @@ -621,13 +621,14 @@ void interval_map_decompose(struct expr *set)
>  	mpz_bitmask(i->value, i->len);
>
>  	if (!mpz_cmp(i->value, expr_value(low)->value)) {
> -		expr_free(i);
>  		compound_expr_add(set, low);
>  	} else {
>  		add_interval(set, low, i);
>  		expr_free(low);
>  	}
>
> +	expr_free(i);
> +
>  out:
>  	if (catchall)
>  		compound_expr_add(set, catchall);
>

Thanks,

J.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]