Hello Edward Cree,
The patch c3bb5c6acd4e: "sfc: functions to register for conntrack
zone offload" from Aug 7, 2023 (linux-next), leads to the following
Smatch static checker warning:
drivers/net/ethernet/sfc/tc_conntrack.c:488 efx_tc_ct_register_zone()
error: 'old' dereferencing possible ERR_PTR()
drivers/net/ethernet/sfc/tc_conntrack.c
469 struct efx_tc_ct_zone *efx_tc_ct_register_zone(struct efx_nic *efx, u16 zone,
470 struct nf_flowtable *ct_ft)
471 {
472 struct efx_tc_ct_zone *ct_zone, *old;
473 int rc;
474
475 ct_zone = kzalloc(sizeof(*ct_zone), GFP_USER);
476 if (!ct_zone)
477 return ERR_PTR(-ENOMEM);
478 ct_zone->zone = zone;
479 old = rhashtable_lookup_get_insert_fast(&efx->tc->ct_zone_ht,
480 &ct_zone->linkage,
481 efx_tc_ct_zone_ht_params);
482 if (old) {
483 /* don't need our new entry */
484 kfree(ct_zone);
485 if (!refcount_inc_not_zero(&old->ref))
rhashtable_lookup_get_insert_fast() can return NULL or error pointers.
486 return ERR_PTR(-EAGAIN);
487 /* existing entry found */
--> 488 WARN_ON_ONCE(old->nf_ft != ct_ft);
489 netif_dbg(efx, drv, efx->net_dev,
490 "Found existing ct_zone for %u\n", zone);
491 return old;
492 }
493 ct_zone->nf_ft = ct_ft;
494 ct_zone->efx = efx;
495 INIT_LIST_HEAD(&ct_zone->cts);
496 mutex_init(&ct_zone->mutex);
497 rc = nf_flow_table_offload_add_cb(ct_ft, efx_tc_flow_block, ct_zone);
498 netif_dbg(efx, drv, efx->net_dev, "Adding new ct_zone for %u, rc %d\n",
499 zone, rc);
500 if (rc < 0)
501 goto fail;
502 refcount_set(&ct_zone->ref, 1);
503 return ct_zone;
504 fail:
505 rhashtable_remove_fast(&efx->tc->ct_zone_ht, &ct_zone->linkage,
506 efx_tc_ct_zone_ht_params);
507 kfree(ct_zone);
508 return ERR_PTR(rc);
509 }
regards,
dan carpenter
