Adding the following warning ...
WARN_ON_ONCE(msk->pm.local_addr_used == 0)
... before decrementing the local_addr_used counter helped to find a bug when running the "remove single address" subtest from the mptcp_join.sh selftests.
Removing a 'signal' endpoint will trigger the removal of all subflows linked to this endpoint via mptcp_pm_nl_rm_addr_or_subflow() with rm_type == MPTCP_MIB_RMSUBFLOW. This will decrement the local_addr_used counter, which is wrong in this case because this counter is linked to 'subflow' endpoints, and here it is a 'signal' endpoint that is being removed.
Now, the counter is decremented, only if the ID is being used outside of mptcp_pm_nl_rm_addr_or_subflow(), only for 'subflow' endpoints, and if the ID is not 0 -- local_addr_used is not taking into account these ones. This marking of the ID as being available, and the decrement is done no matter if a subflow using this ID is currently available, because the subflow could have been closed before.
Fixes: 06faa2271034 ("mptcp: remove multi addresses and subflows in PM") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- net/mptcp/pm_netlink.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 44fc1c5959ac..4cf7cc851f80 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -833,10 +833,10 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk, if (rm_type == MPTCP_MIB_RMSUBFLOW) __MPTCP_INC_STATS(sock_net(sk), rm_type); } - if (rm_type == MPTCP_MIB_RMSUBFLOW) - __set_bit(rm_id ? rm_id : msk->mpc_endpoint_id, msk->pm.id_avail_bitmap); - else if (rm_type == MPTCP_MIB_RMADDR) + + if (rm_type == MPTCP_MIB_RMADDR) __MPTCP_INC_STATS(sock_net(sk), rm_type); + if (!removed) continue;
@@ -846,8 +846,6 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk, if (rm_type == MPTCP_MIB_RMADDR) { msk->pm.add_addr_accepted--; WRITE_ONCE(msk->pm.accept_addr, true); - } else if (rm_type == MPTCP_MIB_RMSUBFLOW) { - msk->pm.local_addr_used--; } } } @@ -1441,6 +1439,14 @@ static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk, return ret; }
+static void __mark_subflow_endp_available(struct mptcp_sock *msk, u8 id) +{ + /* If it was marked as used, and not ID 0, decrement local_addr_used */ + if (!__test_and_set_bit(id ? : msk->mpc_endpoint_id, msk->pm.id_avail_bitmap) && + id && !WARN_ON_ONCE(msk->pm.local_addr_used == 0)) + msk->pm.local_addr_used--; +} + static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net, const struct mptcp_pm_addr_entry *entry) { @@ -1474,11 +1480,11 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net, spin_lock_bh(&msk->pm.lock); mptcp_pm_nl_rm_subflow_received(msk, &list); spin_unlock_bh(&msk->pm.lock); - } else if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) { - /* If the subflow has been used, but now closed */ + } + + if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) { spin_lock_bh(&msk->pm.lock); - if (!__test_and_set_bit(entry->addr.id, msk->pm.id_avail_bitmap)) - msk->pm.local_addr_used--; + __mark_subflow_endp_available(msk, list.ids[0]); spin_unlock_bh(&msk->pm.lock); }
@@ -1516,6 +1522,7 @@ static int mptcp_nl_remove_id_zero_address(struct net *net, spin_lock_bh(&msk->pm.lock); mptcp_pm_remove_addr(msk, &list); mptcp_pm_nl_rm_subflow_received(msk, &list); + __mark_subflow_endp_available(msk, 0); spin_unlock_bh(&msk->pm.lock); release_sock(sk);
@@ -1917,6 +1924,7 @@ static void mptcp_pm_nl_fullmesh(struct mptcp_sock *msk,
spin_lock_bh(&msk->pm.lock); mptcp_pm_nl_rm_subflow_received(msk, &list); + __mark_subflow_endp_available(msk, list.ids[0]); mptcp_pm_create_subflow_or_signal_addr(msk); spin_unlock_bh(&msk->pm.lock); }