From nobody Wed May 15 01:52:32 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 E0E0047F46 for ; Wed, 21 Feb 2024 11:47:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708516072; cv=none; b=gZGqzRaKVAGkb86wORdAth6eI4rdfZAbZhg0nnekn6ccgLlkN0gYOUft82BVj5n8Wr6pp7VGPsFuPOjDKmt3MTRbnvp7wR6IYkT8Sd2lpFwwAi32zCabEnTcCi5GwvnBW6JEZUX5tmjOhB+hgsO39WBqLXY5Z6yBEYR0qX2sqpg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708516072; c=relaxed/simple; bh=LCfcHdVQdcl/Gi4bY9HEk6uAfHdfc1kKfgVRi99z7jg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KVrVLMJC4DrXUO6foNxJVnBPLNVfmWZRfEMd5XCojkrA0CMbsrybnXy3xcmgzMMZnekrd+bnCJcGUKHsLO1tCDCo/8DYbvRMigAb+Xp7cTnU+kNXTE1Ai3wD/3VRvXl9kQ7+X9eWezRPMQnfd101XcpgjQtwLqEK5seO5Lv7Elk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=BJrV+rN7; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BJrV+rN7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708516051; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qQymLmjohQlW5b0pHcwFfJMWUP3T/rM+9zz1QnFwPts=; b=BJrV+rN77q0IV3vJNho6FRlLXJbOF8WR2PbrXMguBuTMzrgVGLXg2s4gK+am988T2sCrqb bMhAi1IVqUOrLLPtxC2yanFkryeLhlenXaNkTa3MRZiDwQjpCopEmH1gWF02vQQ5w2Dk63 2lXar2yJkZAuI7Zz8tM7yr2sFHE3wQM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-333-dpBSw2ExPDGrHMZYvcqd7g-1; Wed, 21 Feb 2024 06:47:26 -0500 X-MC-Unique: dpBSw2ExPDGrHMZYvcqd7g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 42C1E85A58B; Wed, 21 Feb 2024 11:47:26 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.45.224.94]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7446DC0348B; Wed, 21 Feb 2024 11:47:24 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: Matthieu Baerts , Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Shuah Khan , mptcp@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH net 1/2] mptcp: fix possible deadlock in subflow diag Date: Wed, 21 Feb 2024 12:46:58 +0100 Message-ID: In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 Content-Type: text/plain; charset="utf-8" Syzbot and Eric reported a lockdep splat in the subflow diag: WARNING: possible circular locking dependency detected 6.8.0-rc4-syzkaller-00212-g40b9385dd8e6 #0 Not tainted syz-executor.2/24141 is trying to acquire lock: ffff888045870130 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: tcp_diag_put_ulp net/ipv4/tcp_diag.c:100 [inline] ffff888045870130 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: tcp_diag_get_aux+0x738/0x830 net/ipv4/tcp_diag.c:137 but task is already holding lock: ffffc9000135e488 (&h->lhash2[i].lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffffc9000135e488 (&h->lhash2[i].lock){+.+.}-{2:2}, at: inet_diag_dump_icsk+0x39f/0x1f80 net/ipv4/inet_diag.c:1038 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&h->lhash2[i].lock){+.+.}-{2:2}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __inet_hash+0x335/0xbe0 net/ipv4/inet_hashtables.c:743 inet_csk_listen_start+0x23a/0x320 net/ipv4/inet_connection_sock.c:1261 __inet_listen_sk+0x2a2/0x770 net/ipv4/af_inet.c:217 inet_listen+0xa3/0x110 net/ipv4/af_inet.c:239 rds_tcp_listen_init+0x3fd/0x5a0 net/rds/tcp_listen.c:316 rds_tcp_init_net+0x141/0x320 net/rds/tcp.c:577 ops_init+0x352/0x610 net/core/net_namespace.c:136 __register_pernet_operations net/core/net_namespace.c:1214 [inline] register_pernet_operations+0x2cb/0x660 net/core/net_namespace.c:1283 register_pernet_device+0x33/0x80 net/core/net_namespace.c:1370 rds_tcp_init+0x62/0xd0 net/rds/tcp.c:735 do_one_initcall+0x238/0x830 init/main.c:1236 do_initcall_level+0x157/0x210 init/main.c:1298 do_initcalls+0x3f/0x80 init/main.c:1314 kernel_init_freeable+0x42f/0x5d0 init/main.c:1551 kernel_init+0x1d/0x2a0 init/main.c:1441 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242 -> #0 (k-sk_lock-AF_INET6){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18ca/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 lock_sock_fast include/net/sock.h:1723 [inline] subflow_get_info+0x166/0xd20 net/mptcp/diag.c:28 tcp_diag_put_ulp net/ipv4/tcp_diag.c:100 [inline] tcp_diag_get_aux+0x738/0x830 net/ipv4/tcp_diag.c:137 inet_sk_diag_fill+0x10ed/0x1e00 net/ipv4/inet_diag.c:345 inet_diag_dump_icsk+0x55b/0x1f80 net/ipv4/inet_diag.c:1061 __inet_diag_dump+0x211/0x3a0 net/ipv4/inet_diag.c:1263 inet_diag_dump_compat+0x1c1/0x2d0 net/ipv4/inet_diag.c:1371 netlink_dump+0x59b/0xc80 net/netlink/af_netlink.c:2264 __netlink_dump_start+0x5df/0x790 net/netlink/af_netlink.c:2370 netlink_dump_start include/linux/netlink.h:338 [inline] inet_diag_rcv_msg_compat+0x209/0x4c0 net/ipv4/inet_diag.c:1405 sock_diag_rcv_msg+0xe7/0x410 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367 netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 As noted by Eric we can break the lock dependency chain avoid dumping any extended info for the mptcp subflow listener: nothing actually useful is presented there. Fixes: b8adb69a7d29 ("mptcp: fix lockless access in subflow ULP diag") Reported-by: Eric Dumazet Suggested-by: Eric Dumazet Signed-off-by: Paolo Abeni --- net/mptcp/diag.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/mptcp/diag.c b/net/mptcp/diag.c index 6ff6f14674aa..7017dd60659d 100644 --- a/net/mptcp/diag.c +++ b/net/mptcp/diag.c @@ -21,6 +21,9 @@ static int subflow_get_info(struct sock *sk, struct sk_bu= ff *skb) bool slow; int err; =20 + if (inet_sk_state_load(sk) =3D=3D TCP_LISTEN) + return 0; + start =3D nla_nest_start_noflag(skb, INET_ULP_INFO_MPTCP); if (!start) return -EMSGSIZE; --=20 2.43.0 From nobody Wed May 15 01:52:32 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 C577247A6B for ; Wed, 21 Feb 2024 11:47:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708516063; cv=none; b=igPK9Gs+up/V37S7GttyCRiOcN8EpyXAOQBHizdTg5usa5rBE1RoLJ+Fa0SRElSlCoZoNmKOxPEKYTxv1owIqCeSiqXwY3gtGR0RzPaeXeBj1SmbSxjAapWlHaJyRQNom04koLRP6cwMKNnumRWLApk9QIxoCve+pmlGqKv2LAo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708516063; c=relaxed/simple; bh=JBY/mQDw97iHpPVXUG6l2AiWrlYst7bhafK07ofrkEI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nduMbT4bTigxhHYu43biHG7Uxb8YWM8o2RJH7pzHAIPdw3GBTufUPYSIsSC33tZLTCCx+NAHe6Lyx/OgUhAqwfQoHDsWcEy9gH9ss0kj7Jq71fcWHHwHj1lnGBKenPsuDQs2TQ0vcowyJGBK3Twq/zB3T1ABNR69P8ukp8E+yoQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=eiROzVRF; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eiROzVRF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708516050; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XYtHO8q8zxUSZSdp33YY0/GjFEJNFZGA2uUDD/K00Mg=; b=eiROzVRFSb7HJRfejh4zKdM/6wkE7RIgnTGjMHnCecMiydzBHemKPKkgalg5/ncDdtmakU /vTGTdc5jWmEqbH7PIoVhBJ0Y3vGNcfZYStckEkDUhx41I7kTNC6mniBaV12FC0tF7OXPj nz1K9nAWC4RAJf9Ak09RGPbnRQt2YGk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-444-l1e2WZA9PjmHEE1vlZXNnA-1; Wed, 21 Feb 2024 06:47:29 -0500 X-MC-Unique: l1e2WZA9PjmHEE1vlZXNnA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5638785A588; Wed, 21 Feb 2024 11:47:28 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.45.224.94]) by smtp.corp.redhat.com (Postfix) with ESMTP id 87354C08496; Wed, 21 Feb 2024 11:47:26 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: Matthieu Baerts , Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Shuah Khan , mptcp@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH net 2/2] selftests: mptcp: explicitly trigger the listener diag code-path Date: Wed, 21 Feb 2024 12:46:59 +0100 Message-ID: <1116d80f808ea870f3f77fe927dbd6c622d062ae.1708515908.git.pabeni@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 Content-Type: text/plain; charset="utf-8" The mptcp diag interface already experienced a few locking bugs that lockdep and appropriate coverage have detected in advance. Let's add a test-case triggering the relevant code path, to prevent similar issues in the future. Signed-off-by: Paolo Abeni --- tools/testing/selftests/net/mptcp/diag.sh | 30 +++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/tools/testing/selftests/net/mptcp/diag.sh b/tools/testing/self= tests/net/mptcp/diag.sh index 60a7009ce1b5..3ab584b38566 100755 --- a/tools/testing/selftests/net/mptcp/diag.sh +++ b/tools/testing/selftests/net/mptcp/diag.sh @@ -81,6 +81,21 @@ chk_msk_nr() __chk_msk_nr "grep -c token:" "$@" } =20 +chk_listener_nr() +{ + local expected=3D$1 + local msg=3D"$2" + + if [ $expected -gt 0 ] && \ + ! mptcp_lib_kallsyms_has "mptcp_diag_dump_listeners"; then + printf "%-50s%s\n" "$msg - mptcp" "[ skip ]" + mptcp_lib_result_skip "many listener sockets" + else + __chk_nr "ss -inmlHMON $ns | wc -l" "$expected" "$msg - mptcp" + fi + __chk_nr "ss -inmlHtON $ns | wc -l" "$expected" "$msg - subflows" +} + wait_msk_nr() { local condition=3D"grep -c token:" @@ -279,5 +294,20 @@ flush_pids chk_msk_inuse 0 "many->0" chk_msk_cestab 0 "many->0" =20 +chk_listener_nr 0 "no listener sockets" +NR_SERVERS=3D100 +for I in $(seq 1 $NR_SERVERS); do + ip netns exec $ns ./mptcp_connect -p $((I + 20001)) -l 0.0.0.0 2>&1 >/dev= /null & + mptcp_lib_wait_local_port_listen $ns $((I + 20001)) +done + +chk_listener_nr $NR_SERVERS "many listener sockets" + +# gracefull termination +for I in $(seq 1 $NR_SERVERS); do + echo a | ip netns exec $ns ./mptcp_connect -p $((I + 20001)) 127.0.0.1 2>= &1 >/dev/null +done +flush_pids + mptcp_lib_result_print_all_tap exit $ret --=20 2.43.0