[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20240819-net-mptcp-pm-reusing-id-v1-9-38035d40de5b@kernel.org>
Date: Mon, 19 Aug 2024 21:45:27 +0200
From: "Matthieu Baerts (NGI0)" <matttbe@...nel.org>
To: mptcp@...ts.linux.dev, Mat Martineau <martineau@...nel.org>,
Geliang Tang <geliang@...nel.org>, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, Shuah Khan <shuah@...nel.org>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org,
"Matthieu Baerts (NGI0)" <matttbe@...nel.org>, stable@...r.kernel.org
Subject: [PATCH net 09/14] mptcp: pm: only decrement add_addr_accepted for
MPJ req
Adding the following warning ...
WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)
... before decrementing the add_addr_accepted counter helped to find a
bug when running the "remove single subflow" subtest from the
mptcp_join.sh selftest.
Removing a 'subflow' endpoint will first trigger a RM_ADDR, then the
subflow closure. Before this patch, and upon the reception of the
RM_ADDR, the other peer will then try to decrement this
add_addr_accepted. That's not correct because the attached subflows have
not been created upon the reception of an ADD_ADDR.
A way to solve that is to decrement the counter only if the attached
subflow was an MP_JOIN to a remote id that was not 0, and initiated by
the host receiving the RM_ADDR.
Fixes: d0876b2284cf ("mptcp: add the incoming RM_ADDR support")
Cc: stable@...r.kernel.org
Reviewed-by: Mat Martineau <martineau@...nel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@...nel.org>
---
net/mptcp/pm_netlink.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 4cf7cc851f80..882781571c7b 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -829,7 +829,7 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
mptcp_close_ssk(sk, ssk, subflow);
spin_lock_bh(&msk->pm.lock);
- removed = true;
+ removed |= subflow->request_join;
if (rm_type == MPTCP_MIB_RMSUBFLOW)
__MPTCP_INC_STATS(sock_net(sk), rm_type);
}
@@ -843,7 +843,11 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
if (!mptcp_pm_is_kernel(msk))
continue;
- if (rm_type == MPTCP_MIB_RMADDR) {
+ if (rm_type == MPTCP_MIB_RMADDR && rm_id &&
+ !WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)) {
+ /* Note: if the subflow has been closed before, this
+ * add_addr_accepted counter will not be decremented.
+ */
msk->pm.add_addr_accepted--;
WRITE_ONCE(msk->pm.accept_addr, true);
}
--
2.45.2
Powered by blists - more mailing lists