From: Fan Ye tb_xdomain_alloc_in_hopid() passes the wanted HopID to ida_alloc_range() as the lower bound, so a taken id is not an error there: the allocator returns the next free one above it. tbnet_connected_work() asks for the peer's transmit path, treats any other id as a failure and returns without releasing what it got, so that allocation stays live for the rest of the XDomain connection with nothing left holding a reference to it. Release the id when it is not the one we asked for, the same way the error unwind at the end of the function releases the expected one. Fixes: 180b0689425c ("thunderbolt: Allow multiple DMA tunnels over a single XDomain connection") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-5 Signed-off-by: Fan Ye Acked-by: Mika Westerberg --- Reached without fault injection on an ASMedia ASM4242 host-to-host link when the peer drops out mid bring-up: 23 times across two hosts in one run of interface down/up cycling. Each one ended in the XDomain connection being rebuilt, which recreates the ida and disposes of the leaked id, so what I am claiming here is the leak, not a symptom. Patch 2/2 edits the lines this one adds and will not apply without it. v3: - Rewrote the commit message; dropped the quoted source and probe output. v2: https://lore.kernel.org/netdev/20260810-b4-tbnet-hopid-v2-0-0eee557e75df@gmail.com/ --- drivers/net/thunderbolt/main.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/thunderbolt/main.c b/drivers/net/thunderbolt/main.c index 98893732bc6e..e5199a87ea7a 100644 --- a/drivers/net/thunderbolt/main.c +++ b/drivers/net/thunderbolt/main.c @@ -647,6 +647,8 @@ static void tbnet_connected_work(struct work_struct *work) 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"); + if (ret >= 0) + tb_xdomain_release_in_hopid(net->xd, ret); return; } -- 2.43.0