From: Paolo Abeni Date: Thu, 9 Mar 2023 14:50:04 +0000 (+0100) Subject: mptcp: fix lockdep false positive in mptcp_pm_nl_create_listen_socket() X-Git-Tag: baikal/mips/sdk6.1~36 X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=6738eeeef1c7989f7f6ee4b25845e0fce97e32bb;p=kernel.git mptcp: fix lockdep false positive in mptcp_pm_nl_create_listen_socket() commit 1c6801ff728db051120bd48f86b83e2410c8fb26 upstream. Christoph reports a lockdep splat in the mptcp_subflow_create_socket() error path, when such function is invoked by mptcp_pm_nl_create_listen_socket(). Such code path acquires two separates, nested socket lock, with the internal lock operation lacking the "nested" annotation. Adding that in sock_release() for mptcp's sake only could be confusing. Instead just add a new lockclass to the in-kernel msk socket, re-initializing the lockdep infra after the socket creation. Fixes: 8f1319551a64 ("mptcp: fix locking for in-kernel listener creation") Cc: stable@vger.kernel.org Reported-by: Christoph Paasch Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/354 Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts Tested-by: Christoph Paasch Signed-off-by: Matthieu Baerts Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 5e38a0abbabae..1c69e476f4ad6 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -987,9 +987,13 @@ out: return ret; } +static struct lock_class_key mptcp_slock_keys[2]; +static struct lock_class_key mptcp_keys[2]; + static int mptcp_pm_nl_create_listen_socket(struct sock *sk, struct mptcp_pm_addr_entry *entry) { + bool is_ipv6 = sk->sk_family == AF_INET6; int addrlen = sizeof(struct sockaddr_in); struct sockaddr_storage addr; struct socket *ssock; @@ -1006,6 +1010,18 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk, if (!newsk) return -EINVAL; + /* The subflow socket lock is acquired in a nested to the msk one + * in several places, even by the TCP stack, and this msk is a kernel + * socket: lockdep complains. Instead of propagating the _nested + * modifiers in several places, re-init the lock class for the msk + * socket to an mptcp specific one. + */ + sock_lock_init_class_and_name(newsk, + is_ipv6 ? "mlock-AF_INET6" : "mlock-AF_INET", + &mptcp_slock_keys[is_ipv6], + is_ipv6 ? "msk_lock-AF_INET6" : "msk_lock-AF_INET", + &mptcp_keys[is_ipv6]); + lock_sock(newsk); ssock = __mptcp_nmpc_socket(mptcp_sk(newsk)); release_sock(newsk);