[PATCH net] ice: fix metadata_dst refcount handling on representor teardown

[PATCH net] ice: fix metadata_dst refcount handling on representor teardown

[Tristan Madani]

From: Tristan Madani <tristan@talencesecurity.com>

ice_eswitch_release_repr() uses metadata_dst_free() to release the
representor's metadata_dst.  metadata_dst_free() directly frees the
underlying memory without checking the dst_entry refcount.

When ice_eswitch_port_start_xmit() processes a packet, it takes a
reference via dst_hold() and attaches the metadata_dst to the skb.
If the representor is torn down while packets are still queued on
the lower device (e.g. in a qdisc), the metadata_dst is freed while
references are still held.

Use dst_release() instead, which correctly decrements the refcount
and only frees the object when all references are dropped.  The dst
subsystem already handles metadata_dst cleanup in dst_destroy() when
DST_METADATA is set.

Other drivers sharing this pattern (nfp, airoha, bnxt) already use
dst_release() for their metadata_dst lifecycle.

Fixes: f5396b8a663f7 ("ice: switchdev slow path")
Cc: stable@vger.kernel.org
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
---
 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 c30e27bbfe6e2..96174fca3984a 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);
-- 
2.47.3