Hello Ido Schimmel,
The patch 48bb9eb47b27: "netdevsim: fib: Add dummy implementation for
FIB offload" from Jan 14, 2020, leads to the following static checker
warning:
drivers/net/netdevsim/fib.c:663 nsim_fib6_rt_insert()
error: 'fib6_rt' dereferencing possible ERR_PTR()
drivers/net/netdevsim/fib.c
460 nsim_fib6_rt_create(struct nsim_fib_data *data,
461 struct fib6_entry_notifier_info *fen6_info)
462 {
463 struct fib6_info *iter, *rt = fen6_info->rt;
464 struct nsim_fib6_rt *fib6_rt;
465 int i = 0;
466 int err;
467
468 fib6_rt = kzalloc(sizeof(*fib6_rt), GFP_ATOMIC);
469 if (!fib6_rt)
470 return NULL;
^^^^^^^^^^^
471
472 nsim_fib_rt_init(data, &fib6_rt->common, &rt->fib6_dst.addr,
473 sizeof(rt->fib6_dst.addr), rt->fib6_dst.plen, AF_INET6,
474 rt->fib6_table->tb6_id);
475
476 /* We consider a multipath IPv6 route as one entry, but it can be made
477 * up from several fib6_info structs (one for each nexthop), so we
478 * add them all to the same list under the entry.
479 */
480 INIT_LIST_HEAD(&fib6_rt->nh_list);
481
482 err = nsim_fib6_rt_nh_add(fib6_rt, rt);
483 if (err)
484 goto err_fib_rt_fini;
485
486 if (!fen6_info->nsiblings)
487 return fib6_rt;
488
489 list_for_each_entry(iter, &rt->fib6_siblings, fib6_siblings) {
490 if (i == fen6_info->nsiblings)
491 break;
492
493 err = nsim_fib6_rt_nh_add(fib6_rt, iter);
494 if (err)
495 goto err_fib6_rt_nh_del;
496 i++;
497 }
498 WARN_ON_ONCE(i != fen6_info->nsiblings);
499
500 return fib6_rt;
501
502 err_fib6_rt_nh_del:
503 list_for_each_entry_continue_reverse(iter, &rt->fib6_siblings,
504 fib6_siblings)
505 nsim_fib6_rt_nh_del(fib6_rt, iter);
506 nsim_fib6_rt_nh_del(fib6_rt, rt);
507 err_fib_rt_fini:
508 nsim_fib_rt_fini(&fib6_rt->common);
509 kfree(fib6_rt);
510 return ERR_PTR(err);
^^^^^^^^^^^^
511 }
This function should either return NULL or error pointers but not both.
When a function returns a mix of error pointers and NULL, the NULL case
should be a special kind of success. For example, we request a feature
like debugfs but it's disabled. That's not an error, but we also can't
return a valid pointer to the debug fs file.
regards,
dan carpenter
