Based on the provided code slice and the identified vulnerability (CWE-476: NULL Pointer Dereference) on line 32, here are five possible patches to address the issue:

Patch 1:
```c
32     table = fib6_get_table(net, tb_id);
33     if (!table) {
34         err = -EAGAIN;
35         goto out;
36     }
```
Add a NULL check immediately after the function call to handle the case where `fib6_get_table` returns NULL.

Patch 2:
```c
32     table = fib6_get_table(net, tb_id);
33     if (table == NULL) {
34         return -EINVAL;
35     }
```
Add a NULL check and return an error code if the table is NULL, avoiding the use of the `goto` statement.

Patch 3:
```c
32     table = fib6_get_table(net, tb_id);
33     if (!table) {
34         pr_err("Failed to get IPv6 table with ID %u\n", tb_id);
35         return -ENOENT;
36     }
```
Add a NULL check with error logging and return a specific error code for better diagnostics.

Patch 4:
```c
31     tb_id = fib_rule_get_table(rule, arg);
32     if (tb_id == 0) {
33         return -EINVAL;
34     }
35     table = fib6_get_table(net, tb_id);
36     if (!table) {
37         err = -EAGAIN;
38         goto out;
39     }
```
Add checks for both the table ID and the returned table to ensure valid input and output.

Patch 5:
```c
32     table = fib6_get_table(net, tb_id);
33     if (IS_ERR_OR_NULL(table)) {
34         err = PTR_ERR(table) ?: -EAGAIN;
35         goto out;
36     }
```
Use the `IS_ERR_OR_NULL` macro to check for both NULL and error pointers, and set the error code accordingly.