From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AED1716F8E9 for ; Wed, 11 Sep 2024 08:35:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726043753; cv=none; b=f+54dHThy88OoL7wvD/h3nfAQqnZ9z+myeUTMbTl1/W+rw95S2aVWnc2J3WjF7MByE+RCoxnUo412PvJAzjEwTtd+rV0YRvLlv1trF8navUxN6DzvMiVmyr1tXa8yUBJG+r8gjGPvkmoWO2MFkmlqn1G6E2Fn5Fj4k9RMMhIqn0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726043753; c=relaxed/simple; bh=fS0/TQEfsBq11o4gEntfeFOaR1kB5IpuIzfVoCfvsQ8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H9ukfHT3jzOyaGfaXF3BJxg7ELkYP+gGPgEuzKuyb1vkLGVV+b5ZRIX1catkUWsu3uh6cJ59M5N+IXmHcUHcAXED23Ho09wjippdcdYcjrsYfR4sECiMZOX22obc9Ph8yfxluh9/QtsXqM4f41EDPZ5TNxUA8NMt44c/2vVa0i4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PqxdTF3i; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PqxdTF3i" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78FBAC4CECC; Wed, 11 Sep 2024 08:35:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726043753; bh=fS0/TQEfsBq11o4gEntfeFOaR1kB5IpuIzfVoCfvsQ8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PqxdTF3iRvNYR4tun9DAhHqslau7qlGUbqDxZPH46KKZwAkpvsh2iHevBEspTAoC7 vdr6q0VzFz2T+FZlfTDBe9+pFpHI8OGjSnAmiMR5qo6H9ubsfzTasD9qgxn/BTusZA m3n2V69M84SCtxRjjmueaK6CyGOaVEp6nr/3ikxn7vH8CjbEj9raR/uTCAolUe6WbJ tIDEo2095d6ZxFqYqH4nfNdJhMJj7VlMITpZcDrG9XSvlfOYQReF0+TwlGnINLl1b3 35y0V5ZkUBuTRVz7T2L/tKnq8bNIa8S6Pmn5hRO8+1zLZMi46J5VfF7FmHq/QMIeMH zT28ht/kFqg/g== From: "Matthieu Baerts (NGI0)" To: syzbot+f4aacdfef2c6a6529c3e@syzkaller.appspotmail.com Cc: patches@lists.linux.dev Subject: [PATCH net v2] mptcp: initialize sock lock with its own lockdep keys Date: Wed, 11 Sep 2024 10:35:50 +0200 Message-ID: <20240911083550.290915-2-matttbe@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <00000000000047043b0621624565@google.com> References: <00000000000047043b0621624565@google.com> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5779; i=matttbe@kernel.org; h=from:subject; bh=+vx8TDphq+IZDaMq3ANbRPxHG0Q3v9XNGklm3oE2GQ4=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBm4VZmik8xlc2Fx7i86FHddibKaGeSJXwKiH1yW 4h4EMWdZoyJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZuFWZgAKCRD2t4JPQmmg c+moEACDB7LJrZcJOb5Ffkz3yNkBntTt6ATkHevS39jkH7eO2XgiafGWh205Z4ND9PiQyAgL3ZB FsxsMzEwsZx3O3tsbhfZ66pTrVJl1wJRsa0f/icTMftx7XRAWZ5/VVjmE28y9lhmDtnAGVFMQip qEEZ5XuyDqzclf0/Fz6WTAB8t1LUqZIjU5+ip/mz8mXNtlf9DTni3mxdahrpUC1CG4Yz9wAoPi0 36A17SVFclkH4SmfKhlMGs0LDm1CaSLJ/naoM7TdrY9LSxqmLOPgjVgUmuozB3LD6bxk//FDosT tHZnWVf96M6joy8mi3b+GvW1+3CiXTXqP9BmWlJBM0oNJNSkCneGuf64Zs/E/MtCcMqXjg4tvVq +APajDLVKX9nZOH9a20VurtXKkGZk/9jB9Ai0Ee2noIfYDeHKKAagyOBgFvmvLo2G99kOe+6/mT kmOSiWTK69nKLqsS09WNFqczEJSNVSCCGiYwHNy9RhOhsSx+1nbxKq5iQb/YzqSmqr109u7qf6V hJ9GsXo6u1uMH6i5nPDfH/wOrLRtfph56btRMGv2Xj8DpecwLDlyhGWXrtSorDqGqeILDr4mrgf 6xNvX+tzi/WstmxwofS4AwAx047mNvhe9CizGnHZX+7g+Flpf/iHJ+qk2Vt0+leGcsKvCeXk/CF iRGQuOhj4y1hVrQ== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: 8bit From: Cong Wang In mptcp_pm_nl_create_listen_socket(), we already initialize mptcp sock lock with mptcp_slock_keys and mptcp_keys. But that is not sufficient, at least mptcp_init_sock() and mptcp_sk_clone_init() still miss it. As reported by syzbot, mptcp_sk_clone_init() is challenging due to that sk_clone_lock() immediately locks the new sock after preliminary initialization. To amend that, introduce ->init_clone() for struct proto and call it right after the sock_lock_init(), so now mptcp sock could initialize the sock lock again with its own lockdep keys. This patch does not fix any real deadlock, it only makes lockdep happy. Fixes: 58b09919626b ("mptcp: create msk early") Reported-by: syzbot+f4aacdfef2c6a6529c3e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f4aacdfef2c6a6529c3e Cc: Matthieu Baerts Cc: Mat Martineau Cc: Geliang Tang Signed-off-by: Cong Wang Link: https://lore.kernel.org/r/20240911042425.978665-1-xiyou.wangcong@gmail.com Signed-off-by: Matthieu Baerts (NGI0) --- include/net/sock.h | 1 + net/core/sock.c | 2 ++ net/mptcp/pm_netlink.c | 16 +--------------- net/mptcp/protocol.c | 22 ++++++++++++++++++++++ net/mptcp/protocol.h | 1 + 5 files changed, 27 insertions(+), 15 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index f51d61fab059..2e06e720071a 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1226,6 +1226,7 @@ struct proto { int (*ioctl)(struct sock *sk, int cmd, int *karg); int (*init)(struct sock *sk); + void (*init_clone)(struct sock *sk); void (*destroy)(struct sock *sk); void (*shutdown)(struct sock *sk, int how); int (*setsockopt)(struct sock *sk, int level, diff --git a/net/core/sock.c b/net/core/sock.c index 468b1239606c..d37e6efc7f91 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2325,6 +2325,8 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) } sk_node_init(&newsk->sk_node); sock_lock_init(newsk); + if (prot->init_clone) + prot->init_clone(newsk); bh_lock_sock(newsk); newsk->sk_backlog.head = newsk->sk_backlog.tail = NULL; newsk->sk_backlog.len = 0; diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index fe34297ea6dc..a82b68cc1faf 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1067,13 +1067,9 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet, 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 sock *newsk, *ssk; @@ -1089,17 +1085,7 @@ 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]); + mptcp_sock_lock_init(newsk); lock_sock(newsk); ssk = __mptcp_nmpc_sk(mptcp_sk(newsk)); diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 3b837765c84b..7ecaa83794b2 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2839,6 +2839,7 @@ static int mptcp_init_sock(struct sock *sk) int ret; __mptcp_init_sock(sk); + mptcp_sock_lock_init(sk); if (!mptcp_is_enabled(net)) return -ENOPROTOOPT; @@ -2865,6 +2866,26 @@ static int mptcp_init_sock(struct sock *sk) return 0; } +static struct lock_class_key mptcp_slock_keys[2]; +static struct lock_class_key mptcp_keys[2]; + +void mptcp_sock_lock_init(struct sock *sk) +{ + bool is_ipv6 = sk->sk_family == AF_INET6; + + /* 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(sk, + 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]); +} + static void __mptcp_clear_xmit(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); @@ -3797,6 +3818,7 @@ static struct proto mptcp_prot = { .name = "MPTCP", .owner = THIS_MODULE, .init = mptcp_init_sock, + .init_clone = mptcp_sock_lock_init, .connect = mptcp_connect, .disconnect = mptcp_disconnect, .close = mptcp_close, diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index c3942416fa3a..819a193c0d88 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -812,6 +812,7 @@ void __init mptcp_proto_init(void); int __init mptcp_proto_v6_init(void); #endif +void mptcp_sock_lock_init(struct sock *sk); struct sock *mptcp_sk_clone_init(const struct sock *sk, const struct mptcp_options_received *mp_opt, struct sock *ssk, -- 2.45.2