From 25e37407442b8766ec2cf52fb4e31b5c3d3aeeae Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Tue, 5 May 2026 17:00:52 +0200 Subject: [PATCH] mptcp: pm: ADD_ADDR rtx: always decrease sk refcount commit 9634cb35af17019baec21ca648516ce376fa10e6 upstream. When an ADD_ADDR is retransmitted, the sk is held in sk_reset_timer(). It should then be released in all cases at the end. Some (unlikely) checks were returning directly instead of calling sock_put() to decrease the refcount. Jump to a new 'exit' label to call __sock_put() (which will become sock_put() in the next commit) to fix this potential leak. While at it, drop the '!msk' check which cannot happen because it is never reset, and explicitly mark the remaining one as "unlikely". Fixes: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260505-net-mptcp-pm-fixes-7-1-rc3-v1-4-fca8091060a4@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/pm.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index 24295517711b4..37e48381ddebe 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -344,11 +344,8 @@ static void mptcp_pm_add_timer(struct timer_list *timer) pr_debug("msk=%p\n", msk); - if (!msk) - return; - - if (inet_sk_state_load(sk) == TCP_CLOSE) - return; + if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE)) + goto exit; bh_lock_sock(sk); if (sock_owned_by_user(sk)) { @@ -386,6 +383,7 @@ static void mptcp_pm_add_timer(struct timer_list *timer) out: bh_unlock_sock(sk); +exit: __sock_put(sk); } -- 2.47.3