On Tue, Sep 1, 2026 at 11:04 PM Jacob Tanenbaum via dev <
[email protected]> wrote:
> Performing dynamic_bitmap_or() can change the number of elements,
> causing n_elems to potentially not reflect the number of elements in the
> bitmap. Recalculate the n_elems in dynamic_bitmap_or().
>
> Fixes: 2d2e1e600fd0 ("util: Improve dynamic_bitmap APIs.")
> Assisted-by: Claude Opus 4.8, Claude Code
> Signed-off-by: Jacob Tanenbaum <[email protected]>
> ---
> lib/ovn-util.h | 1 +
> tests/ovn.at | 1 +
> tests/test-sparse-array.c | 54 ++++++++++++++++++++++++++++++++++++---
> 3 files changed, 53 insertions(+), 3 deletions(-)
>
> diff --git a/lib/ovn-util.h b/lib/ovn-util.h
> index 3ffcf42c3..9897db8f0 100644
> --- a/lib/ovn-util.h
> +++ b/lib/ovn-util.h
> @@ -640,6 +640,7 @@ dynamic_bitmap_or(struct dynamic_bitmap *db,
> {
> ovs_assert(db->capacity == n);
> bitmap_or(db->map, arg, n);
> + db->n_elems = bitmap_count1(db->map, db->capacity);
>
nit: dynamic_bitmap_count1(db).
> }
>
> static inline unsigned long *
> diff --git a/tests/ovn.at b/tests/ovn.at
> index b9fdb9c98..7e5eb301e 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -2458,6 +2458,7 @@ AT_CLEANUP
> AT_SETUP([Sparse array operations])
> check ovstest test-sparse-array add
> check ovstest test-sparse-array remove-replace
> +check ovstest test-sparse-array bitmap-or
> AT_CLEANUP
>
> AT_SETUP([SPSC ring buffer])
> diff --git a/tests/test-sparse-array.c b/tests/test-sparse-array.c
> index 3948ba884..4258550c1 100644
> --- a/tests/test-sparse-array.c
> +++ b/tests/test-sparse-array.c
> @@ -188,14 +188,62 @@ test_remove_replace(struct ovs_cmdl_context *ctx
> OVS_UNUSED)
> free(item_five);
> }
>
> +static void
> +test_dynamic_bitmap_or(struct ovs_cmdl_context *ctx OVS_UNUSED)
> +{
> + struct dynamic_bitmap a, b;
> +
> + dynamic_bitmap_alloc(&a, 8);
> + dynamic_bitmap_alloc(&b, 8);
> +
> + /* Set bits 1, 3 in 'a' through the tracked API. */
> + dynamic_bitmap_set1(&a, 1);
> + dynamic_bitmap_set1(&a, 3);
> + ovs_assert(a.n_elems == 2);
> +
> + /* Set bits 3, 5, 7 in 'b'. */
> + dynamic_bitmap_set1(&b, 3);
> + dynamic_bitmap_set1(&b, 5);
> + dynamic_bitmap_set1(&b, 7);
> + ovs_assert(b.n_elems == 3);
> +
> + /* OR 'b' into 'a'. Result should be {1, 3, 5, 7} = 4 elements.
> + * Before the fix, n_elems stayed at 2 because dynamic_bitmap_or
> + * did not recount. */
> + dynamic_bitmap_or(&a, b.map, b.capacity);
> + ovs_assert(a.n_elems == 4);
> + ovs_assert(dynamic_bitmap_is_set(&a, 1));
> + ovs_assert(dynamic_bitmap_is_set(&a, 3));
> + ovs_assert(dynamic_bitmap_is_set(&a, 5));
> + ovs_assert(dynamic_bitmap_is_set(&a, 7));
> + ovs_assert(!dynamic_bitmap_is_set(&a, 0));
> + ovs_assert(!dynamic_bitmap_is_set(&a, 2));
> +
> + /* Clearing a bit that was added by the OR must not underflow
> + * n_elems. Before the fix, n_elems was 2 here so clearing two
> + * OR-added bits would wrap to SIZE_MAX. */
> + dynamic_bitmap_set0(&a, 5);
> + ovs_assert(a.n_elems == 3);
> + dynamic_bitmap_set0(&a, 7);
> + ovs_assert(a.n_elems == 2);
> + dynamic_bitmap_set0(&a, 1);
> + ovs_assert(a.n_elems == 1);
> + dynamic_bitmap_set0(&a, 3);
> + ovs_assert(a.n_elems == 0);
> +
> + dynamic_bitmap_free(&a);
> + dynamic_bitmap_free(&b);
> +}
> +
> static void
> test_sparse_array_main(int argc OVS_UNUSED, char *argv[] OVS_UNUSED)
> {
> ovn_set_program_name(argv[0]);
> static const struct ovs_cmdl_command commands[] = {
> - {"add", NULL, 0, 0, test_add, OVS_RO},
> - {"remove-replace", NULL, 0, 0, test_remove_replace, OVS_RO},
> - {NULL, NULL, 0, 0, NULL, OVS_RO},
> + {"add", NULL, 0, 0, test_add, OVS_RO},
> + {"remove-replace", NULL, 0, 0, test_remove_replace, OVS_RO},
> + {"bitmap-or", NULL, 0, 0, test_dynamic_bitmap_or, OVS_RO},
> + {NULL, NULL, 0, 0, NULL, OVS_RO},
> };
> struct ovs_cmdl_context ctx;
> ctx.argc = argc - 1;
> --
> 2.55.0
>
> _______________________________________________
> dev mailing list
> [email protected]
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
>
Thank you Jacob,
applied to main, with the nit fixed, and backported down to 26.03.
Regards,
Ales
_______________________________________________
dev mailing list
[email protected]
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
