2018-07-17 1:09 GMT+09:00 Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>:
> Hi Taehee,
>
> On Tue, Jul 10, 2018 at 11:22:01PM +0900, Taehee Yoo wrote:
>> This patch fixes below.
>> 1. check null pointer of rb_next.
>> rb_next can return null. so null check routine should be added.
>> 2. add rcu_barrier in destroy routine.
>> GC uses call_rcu to remove elements. but all elements should be
>> removed before destroying set and chains. so that rcu_barrier is added.
> [...]
>> diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c
>> index 1f8f257..09e3a15 100644
>> --- a/net/netfilter/nft_set_rbtree.c
>> +++ b/net/netfilter/nft_set_rbtree.c
>> @@ -381,7 +381,7 @@ static void nft_rbtree_gc(struct work_struct *work)
>>
>> gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC);
>> if (!gcb)
>> - goto out;
>> + break;
>>
>> atomic_dec(&set->nelems);
>> nft_set_gc_batch_add(gcb, rbe);
>> @@ -390,10 +390,12 @@ static void nft_rbtree_gc(struct work_struct *work)
>> rbe = rb_entry(prev, struct nft_rbtree_elem, node);
>> atomic_dec(&set->nelems);
>> nft_set_gc_batch_add(gcb, rbe);
>> + prev = NULL;
>> }
>> node = rb_next(node);
>> + if (!node)
>> + break;
>> }
>> -out:
>> if (gcb) {
>> for (i = 0; i < gcb->head.cnt; i++) {
>> rbe = gcb->elems[i];
>> @@ -440,9 +442,10 @@ static void nft_rbtree_destroy(const struct nft_set *set)
>> struct rb_node *node;
>>
>> cancel_delayed_work_sync(&priv->gc_work);
>> + rcu_barrier();
>> while ((node = priv->root.rb_node) != NULL) {
>> - rb_erase(node, &priv->root);
>> rbe = rb_entry(node, struct nft_rbtree_elem, node);
>> + rb_erase(node, &priv->root);
>
> Just to clarify: Do we have to reorder these lines? I mean, place
> rb_erase() after rb_entry(). Just asking because this is not described
> in the patch description - I just came from long trip, I'm tired so I
> may be overlooking anything. No need to resend in any case.
>
> Let me know, thanks!
Hi Pablo,
It doesn't change actural logic and doesn't fix problem.
I prefer that setting variables on top of while statement.
so I added it.
I'm so sorry to make you confused.
Thanks for reviewing!
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