From: Mat Martineau martineau@kernel.org

When path manager entries are deleted from the local address list, they are first unlinked from the address list using list_del_rcu(). The entries must not be freed until after the RCU grace period, but the existing code immediately frees the entry.

Use kfree_rcu_mightsleep() and adjust sk_omem_alloc in open code instead of using the sock_kfree_s() helper. This code path is only called in a netlink handler, so the "might sleep" function is preferable to adding a rarely-used rcu_head member to struct mptcp_pm_addr_entry.

Fixes: 88d097316371 ("mptcp: drop free_list for deleting entries") Cc: stable@vger.kernel.org Signed-off-by: Mat Martineau martineau@kernel.org Reviewed-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- net/mptcp/pm_userspace.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c index 2cb62f026b1f4420c549ab8ee6f54ffe3880d453..a715dcbe0146ed0c055d071c63257047a90a9afd 100644 --- a/net/mptcp/pm_userspace.c +++ b/net/mptcp/pm_userspace.c @@ -337,7 +337,11 @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)

release_sock(sk);

- sock_kfree_s(sk, match, sizeof(*match)); + kfree_rcu_mightsleep(match); + /* Adjust sk_omem_alloc like sock_kfree_s() does, to match + * with allocation of this memory by sock_kmemdup() + */ + atomic_sub(sizeof(*match), &sk->sk_omem_alloc);

err = 0; out: