Re: [PATCH net v2 1/2] net: thunderbolt: Release the Rx HopID that was handed out on mismatch

On Mon, Aug 10, 2026 at 09:39:14AM +0000, Fan Ye via B4 Relay wrote:

> tbnet_connected_work() asks for a specific input HopID and treats getting
> a different one as a failure:
> 
> 	ret = tb_xdomain_alloc_in_hopid(net->xd, net->remote_transmit_path);
> 	if (ret != net->remote_transmit_path) {
> 		netdev_err(net->dev, "failed to allocate Rx HopID\n");
> 		return;
> 	}

No need to cite the code, we all able to see it well from the source tree.

> That call ends in ida_alloc_range(&xd->in_hopids, hopid,
> xd->local_max_hopid, GFP_KERNEL), which allocates the lowest free id at
> or above the one asked for. When the
> wanted HopID is already taken it does not fail - it succeeds with the next
> one - so this path returns with an id allocated and no reference to it
> left anywhere. It stays allocated for the rest of the XDomain connection.
> 
> Forcing the branch by occupying the wanted HopID first shows the returned
> id is a live allocation, not an error code:
> 
>   LEAKPROBE squat=8 requested=8 local_max_hopid=27
>   LEAKPROBE real alloc ret=9
>   thunderbolt-net 0-1.0 thunderbolt0: failed to allocate Rx HopID
> 
> Release the id when it is not the one we wanted, matching what the error
> unwind at the end of the function already does for the expected id.

General hint: do not blindly copy'n'paste the Dostoevsky saga from AI. Squeeze
it and show (by rephrasing) that you also understand what's going on there.

-- 
With Best Regards,
Andy Shevchenko