mptcp: pm: add lockdep assertions

BugLink: https://bugs.launchpad.net/bugs/1921710

[ Upstream commit 3abc05d ]

Add a few assertions to make sure functions are called with the needed
locks held.
Two functions gain might_sleep annotations because they contain
conditional calls to functions that sleep.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

net/mptcp/pm.c

@@ -20,6 +20,8 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 
 	pr_debug("msk=%p, local_id=%d", msk, addr->id);
 
+	lockdep_assert_held(&msk->pm.lock);
+
 	if (add_addr) {
 		pr_warn("addr_signal error, add_addr=%d", add_addr);
 		return -EINVAL;

net/mptcp/pm_netlink.c

@@ -134,6 +134,8 @@ select_local_address(const struct pm_nl_pernet *pernet,
 {
 	struct mptcp_pm_addr_entry *entry, *ret = NULL;
 
+	msk_owned_by_me(msk);
+
 	rcu_read_lock();
 	__mptcp_flush_join_list(msk);
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
@@ -191,6 +193,8 @@ lookup_anno_list_by_saddr(struct mptcp_sock *msk,
 {
 	struct mptcp_pm_add_entry *entry;
 
+	lockdep_assert_held(&msk->pm.lock);
+
 	list_for_each_entry(entry, &msk->pm.anno_list, list) {
 		if (addresses_equal(&entry->addr, addr, false))
 			return entry;
@@ -266,6 +270,8 @@ static bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
 	struct sock *sk = (struct sock *)msk;
 	struct net *net = sock_net(sk);
 
+	lockdep_assert_held(&msk->pm.lock);
+
 	if (lookup_anno_list_by_saddr(msk, &entry->addr))
 		return false;
 
@@ -408,6 +414,9 @@ void mptcp_pm_nl_add_addr_send_ack(struct mptcp_sock *msk)
 {
 	struct mptcp_subflow_context *subflow;
 
+	msk_owned_by_me(msk);
+	lockdep_assert_held(&msk->pm.lock);
+
 	if (!mptcp_pm_should_add_signal(msk))
 		return;
 
@@ -443,6 +452,8 @@ void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
 
 	pr_debug("address rm_id %d", msk->pm.rm_id);
 
+	msk_owned_by_me(msk);
+
 	if (!msk->pm.rm_id)
 		return;
 
@@ -478,6 +489,8 @@ void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id)
 
 	pr_debug("subflow rm_id %d", rm_id);
 
+	msk_owned_by_me(msk);
+
 	if (!rm_id)
 		return;
 

net/mptcp/protocol.c

@@ -2186,6 +2186,8 @@ static void __mptcp_close_subflow(struct mptcp_sock *msk)
 {
 	struct mptcp_subflow_context *subflow, *tmp;
 
+	might_sleep();
+
 	list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 
@@ -2529,6 +2531,8 @@ static void __mptcp_destroy_sock(struct sock *sk)
 
 	pr_debug("msk=%p", msk);
 
+	might_sleep();
+
 	/* dispose the ancillatory tcp socket, if any */
 	if (msk->subflow) {
 		iput(SOCK_INODE(msk->subflow));

net/mptcp/protocol.h

@@ -286,6 +286,11 @@ struct mptcp_sock {
 #define mptcp_for_each_subflow(__msk, __subflow)			\
 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
 
+static inline void msk_owned_by_me(const struct mptcp_sock *msk)
+{
+	sock_owned_by_me((const struct sock *)msk);
+}
+
 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
 {
 	return (struct mptcp_sock *)sk;