From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f197.google.com (mail-il1-f197.google.com [209.85.166.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 403F215445B for ; Wed, 11 Sep 2024 09:06:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726045575; cv=none; b=giZhtLq78nRsXIKErikkxSdnmVo6Ku82r9Xte9YaIyyOZL03qtSi7gXKbykeSW9/iieeTaYE42PLuGc9NRAIxWHVTGkPljtt0Wk2j1aFsaTdaIUHgotXNxRYYgErHY2QHvD5JQS4vxaFDK6ObRUfPM+W4rkwxuPu07C6GxBHAvQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726045575; c=relaxed/simple; bh=McHc0XTZ9m/AKhA60+tEv9WHCGFgjix5e8t8rInyN1Y=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=nbRyRB5pDhELgaguPNOY1/hU5b3NAxShfsMheIQTIDUGb3U0AtYDRsubgKvTee6CfhEolN/NdeJp/+NcI2lCnvnvxFaQt6DxnVntwVZ75wXWPDwg2El75c4AMpHvb2wwwcK9eZJxGYJigsjb9MEm3gNWNjffuAvcE8/JssORJvU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.166.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-il1-f197.google.com with SMTP id e9e14a558f8ab-3a04c905651so92177165ab.2 for ; Wed, 11 Sep 2024 02:06:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726045573; x=1726650373; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=GO1k+k3ZshwQP0aU7q2Qrrg/Vl2KXbr8e7yQd0U4K8g=; b=JHTy4GBJP9DQNB1zVLSj5JZs6u7z7P3J+naev7SL0OuXl1guyMLyBS9PrVJ0Vach9E EGTJhjZ2J/61Z2Hq+e0wdU2ixS+zmL4BDg8pbsGXkVdyZylw97AQ38h9OVjyj2nRB6pV PXhWcIC6uTH2D//iS33lBLMf5PzMOSnMQeEZnJRekHTZoldj4paLERaHi9I/44QK8t/j EcD/N1+A8u2+cO7sFhU4xfkbkiWoF+BVGDPzryci8pQQjYepsRTxlfihfy/CsYlb2d15 HAoqxeJuF95S+oYokFEB3wMpQshzZ6AytX9BLu5lnOac8NR5O2PYrfukxXdcte922Be5 51AA== X-Gm-Message-State: AOJu0YwIlPqcQkpLuV6Q7a5afGSYbS5ysYoYMoaZJwK+hHIbMOCbpN9y hP53HmF2UHWmyPZ+5KDqKfISNDQGEZz55dHlZJJl5qeH5KjpDs4J/szDzzVpZXheIq+2oHjoEla aasCl2zTHnyhPJWFDGPXru8YbGkhgKxvaehatBd3bhfrBpvm8Ucyp+JE= X-Google-Smtp-Source: AGHT+IGBu0IWgcvG/OuWjJ/edRcxn2yshQE7C1l3+/UYnqImALcsxDSZ+lyxgc4i4tczSmXc7dYOte3oRKiEsPz8azUH0nxAqx6k Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:12ca:b0:39e:78d9:ebfc with SMTP id e9e14a558f8ab-3a04f0ce281mr219386135ab.17.1726045573395; Wed, 11 Sep 2024 02:06:13 -0700 (PDT) Date: Wed, 11 Sep 2024 02:06:13 -0700 In-Reply-To: <00000000000047043b0621624565@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000044cafe0621d44d72@google.com> Subject: Re: [syzbot] [PATCH net v2] mptcp: initialize sock lock with its own lockdep keys From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH net v2] mptcp: initialize sock lock with its own lockdep keys Author: matttbe@kernel.org 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. #syz test 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