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@xxxxxxxxxxxxxxx
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
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);
}
--
2.45.2
