Re: [PATCH] nf_conntrack_core: Updated nf_conntrack to destroy/refresh conn irrespective of del_timer status

[Patrick McHardy <kaber@trash.net>]

Kapil Juneja wrote:
> Currently NF_CONNTRACK assumes that a running timer is present before refreshing
> the connection or destroying it. This may not be the case when, for example,
> another forwarding engine hooks up to it to listen to new connections
> but disables the NF_CONNTRACK timer in order to have more control.
> In such a scenario, only control packets may be terminated to NF_CONNTRACK for
> it to decode and update the connection status. It will not impact the present
> scenario of kernel forwarding without the aid of any forwarding engine. 

Do you have a pointer to the code you're talking about?

> +		if (newtime - ct->timeout.expires >= HZ) {
> +			/*
> +			 * The timer could have already been deleted
> +			 * while still alive (for example connection
> +			 * offloaded to a forwarding module other than
> +			 * the kernel stack).
> +			 */
> +			mod_timer(&ct->timeout, newtime);
>  			event = IPCT_REFRESH;

This adds a race, we don't want to update the timer if it already
went off this that means the connection is already destroyed.
Same problem with the other chunk.