On 02/24/2019 07:32 PM, Li RongQing wrote:
> This pointer is RCU protected, so proper primitives should be used.
>
> Signed-off-by: Zhang Yu <zhangyu31@xxxxxxxxx>
> Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
> ---
> net/netfilter/xt_CT.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/net/netfilter/xt_CT.c b/net/netfilter/xt_CT.c
> index 0fa863f57575..26dee8bba326 100644
> --- a/net/netfilter/xt_CT.c
> +++ b/net/netfilter/xt_CT.c
> @@ -99,7 +99,7 @@ xt_ct_set_helper(struct nf_conn *ct, const char *helper_name,
> return -ENOMEM;
> }
>
> - help->helper = helper;
> + RCU_INIT_POINTER(help->helper, helper);
> return 0;
> }
>
> @@ -274,7 +274,7 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par,
> err4:
> help = nfct_help(ct);
> if (help)
> - nf_conntrack_helper_put(help->helper);
> + nf_conntrack_helper_put(rcu_dereference(help->helper));
Are you sure it is ok, have you tested your patch ?
Where is the rcu_read_lock() ?
CONFIG_PROVE_RCU=y will likely give a splat here.
> err3:
> nf_ct_tmpl_free(ct);
> err2:
> @@ -357,7 +357,7 @@ static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
> if (ct) {
> help = nfct_help(ct);
> if (help)
> - nf_conntrack_helper_put(help->helper);
> + nf_conntrack_helper_put(rcu_dereference(help->helper));
Same here.
>
> nf_ct_netns_put(par->net, par->family);
>
>
