On Mon, Sep 30, 2019 at 11:08 AM Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote:
>
> BH must be disabled when invoking nf_conncount_gc_list() to perform
> garbage collection, otherwise deadlock might happen.
>
It is working great, thank you. Also, probably this is also desirable for 4.19.
> nf_conncount_add+0x1f/0x50 [nf_conncount]
> nft_connlimit_eval+0x4c/0xe0 [nft_connlimit]
> nft_dynset_eval+0xb5/0x100 [nf_tables]
> nft_do_chain+0xea/0x420 [nf_tables]
> ? sch_direct_xmit+0x111/0x360
> ? noqueue_init+0x10/0x10
> ? __qdisc_run+0x84/0x510
> ? tcp_packet+0x655/0x1610 [nf_conntrack]
> ? ip_finish_output2+0x1a7/0x430
> ? tcp_error+0x130/0x150 [nf_conntrack]
> ? nf_conntrack_in+0x1fc/0x4c0 [nf_conntrack]
> nft_do_chain_ipv4+0x66/0x80 [nf_tables]
> nf_hook_slow+0x44/0xc0
> ip_rcv+0xb5/0xd0
> ? ip_rcv_finish_core.isra.19+0x360/0x360
> __netif_receive_skb_one_core+0x52/0x70
> netif_receive_skb_internal+0x34/0xe0
> napi_gro_receive+0xba/0xe0
> e1000_clean_rx_irq+0x1e9/0x420 [e1000e]
> e1000e_poll+0xbe/0x290 [e1000e]
> net_rx_action+0x149/0x3b0
> __do_softirq+0xde/0x2d8
> irq_exit+0xba/0xc0
> do_IRQ+0x85/0xd0
> common_interrupt+0xf/0xf
> </IRQ>
> RIP: 0010:nf_conncount_gc_list+0x3b/0x130 [nf_conncount]
>
> Fixes: 2f971a8f4255 ("netfilter: nf_conncount: move all list iterations under spinlock")
> Reported-by: Laura Garcia Liebana <nevola@xxxxxxxxx>
> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> ---
> net/netfilter/nft_connlimit.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/net/netfilter/nft_connlimit.c b/net/netfilter/nft_connlimit.c
> index af1497ab9464..69d6173f91e2 100644
> --- a/net/netfilter/nft_connlimit.c
> +++ b/net/netfilter/nft_connlimit.c
> @@ -218,8 +218,13 @@ static void nft_connlimit_destroy_clone(const struct nft_ctx *ctx,
> static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr)
> {
> struct nft_connlimit *priv = nft_expr_priv(expr);
> + bool ret;
>
> - return nf_conncount_gc_list(net, &priv->list);
> + local_bh_disable();
> + ret = nf_conncount_gc_list(net, &priv->list);
> + local_bh_enable();
> +
> + return ret;
> }
>
> static struct nft_expr_type nft_connlimit_type;
> --
> 2.11.0
>
