Cong Wang <xiyou.wangcong@xxxxxxxxx> wrote:
> In clusterip_config_find_get() we hold RCU read lock so it could
> run concurrently with clusterip_config_entry_put(), as a result,
> the refcnt could go back to 1 from 0, which leads to a double
> list_del()... Just replace refcount_inc() with
> refcount_inc_not_zero(), as for c->refcount.
>
> Fixes: d73f33b16883 ("netfilter: CLUSTERIP: RCU conversion")
> Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx>
> Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
> ---
> net/ipv4/netfilter/ipt_CLUSTERIP.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
> index 1ff72b87a066..4537b1686c7c 100644
> --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
> +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
> @@ -154,8 +154,10 @@ clusterip_config_find_get(struct net *net, __be32 clusterip, int entry)
> #endif
> if (unlikely(!refcount_inc_not_zero(&c->refcount)))
> c = NULL;
> - else if (entry)
> - refcount_inc(&c->entries);
> + else if (entry) {
> + if (unlikely(!refcount_inc_not_zero(&c->entries)))
this needs to call clusterip_config_put(c); too, else we leak one
reference.
Other than that this looks good.
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