On 18/06/2026 16:50, Doruk Tan Ozturk wrote:
> ice_eswitch_release_repr() frees the port representor metadata_dst via
> metadata_dst_free(), which directly kfree()s the object and ignores the
> dst_entry refcount. The eswitch slow-path TX routine
> ice_eswitch_port_start_xmit() takes a reference on this dst with
> dst_hold() and attaches it to the skb via skb_dst_set(). If such an skb
> is still in flight (e.g. queued in a qdisc) when the representor is torn
> down, the metadata_dst is freed while the skb still points at it. When
> the skb is later freed, dst_release() operates on already-freed memory.
>
> Replace metadata_dst_free() with dst_release() so the metadata_dst is
> freed only after the last reference is dropped. The dst subsystem frees
> metadata_dst objects from dst_destroy() once the refcount reaches zero
> (DST_METADATA is set by metadata_dst_alloc()).
>
> Same class of bug and fix as commit c32b26aaa2f9 ("netfilter:
> nft_tunnel: fix use-after-free on object destroy").
>
> Fixes: 1a1c40df2e80 ("ice: set and release switchdev environment")
> Cc: [email protected]
> Signed-off-by: Doruk Tan Ozturk <[email protected]>
> Reviewed-by: Simon Horman <[email protected]>
Reviewed-by: Marcin Szycik <[email protected]>
> ---
> v2:
> - Correct the Fixes: tag to 1a1c40df2e80 ("ice: set and release
> switchdev environment"); the previously cited fff292b47ac1 only moved
> the affected code rather than introducing the unbalanced free, and the
> bug dates back to when switchdev support was added (Simon Horman).
> - Add Simon Horman's Reviewed-by. No functional change.
>
> drivers/net/ethernet/intel/ice/ice_eswitch.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice_eswitch.c
> b/drivers/net/ethernet/intel/ice/ice_eswitch.c
> index 2e4f0969035f..41b30a7ca4a9 100644
> --- a/drivers/net/ethernet/intel/ice/ice_eswitch.c
> +++ b/drivers/net/ethernet/intel/ice/ice_eswitch.c
> @@ -95,7 +95,7 @@ ice_eswitch_release_repr(struct ice_pf *pf, struct ice_repr
> *repr)
> return;
>
> ice_vsi_update_security(vsi, ice_vsi_ctx_set_antispoof);
> - metadata_dst_free(repr->dst);
> + dst_release(&repr->dst->dst);
> repr->dst = NULL;
> ice_fltr_add_mac_and_broadcast(vsi, repr->parent_mac,
> ICE_FWD_TO_VSI);
> --
> 2.43.0
