[PATCH net 02/14] mptcp: subflow: no need to copy thmac during ulp_clone

From: Matthieu Baerts (NGI0)

Date: Mon Aug 24 2026 - 12:49:00 EST


'thmac' is not used after that point.

Indeed, subflow_ulp_clone() is called when the request on the passive
side is over, so when the truncated HMAC is no longer needed.

Note that in case of SYN cookies, thmac will not be initialised. So
better to remove it to avoid a warning from debug tools like KMSAN for
reading uninitialised data.

Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Geliang Tang <geliang@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
Cc: Florian Westphal <fw@xxxxxxxxx>
Note: Peter Krystad's email address is bouncing.
---
net/mptcp/subflow.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index af81ad5e699d..01db7edce18a 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -2084,7 +2084,6 @@ static void subflow_ulp_clone(const struct request_sock *req,
new_ctx->request_bkup = subflow_req->request_bkup;
WRITE_ONCE(new_ctx->remote_id, subflow_req->remote_id);
new_ctx->token = subflow_req->token;
- new_ctx->thmac = subflow_req->thmac;

/* the subflow req id is valid, fetched via subflow_check_req()
* and subflow_token_join_request()

--
2.53.0