kernel/linux.git/net/mptcp, branch linux-6.0.y

mptcp: fix lockdep false positive

2023-01-12T11:00:30+00:00

[ Upstream commit fec3adfd754ccc99a7230e8ab9f105b65fb07bcc ] MattB reported a lockdep splat in the mptcp listener code cleanup: WARNING: possible circular locking dependency detected packetdrill/14278 is trying to acquire lock: ffff888017d868f0 ((work_completion)(&msk->work)){+.+.}-{0:0}, at: __flush_work (kernel/workqueue.c:3069) but task is already holding lock: ffff888017d84130 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close (net/mptcp/protocol.c:2973) which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (sk_lock-AF_INET){+.+.}-{0:0}: __lock_acquire (kernel/locking/lockdep.c:5055) lock_acquire (kernel/locking/lockdep.c:466) lock_sock_nested (net/core/sock.c:3463) mptcp_worker (net/mptcp/protocol.c:2614) process_one_work (kernel/workqueue.c:2294) worker_thread (include/linux/list.h:292) kthread (kernel/kthread.c:376) ret_from_fork (arch/x86/entry/entry_64.S:312) -> #0 ((work_completion)(&msk->work)){+.+.}-{0:0}: check_prev_add (kernel/locking/lockdep.c:3098) validate_chain (kernel/locking/lockdep.c:3217) __lock_acquire (kernel/locking/lockdep.c:5055) lock_acquire (kernel/locking/lockdep.c:466) __flush_work (kernel/workqueue.c:3070) __cancel_work_timer (kernel/workqueue.c:3160) mptcp_cancel_work (net/mptcp/protocol.c:2758) mptcp_subflow_queue_clean (net/mptcp/subflow.c:1817) __mptcp_close_ssk (net/mptcp/protocol.c:2363) mptcp_destroy_common (net/mptcp/protocol.c:3170) mptcp_destroy (include/net/sock.h:1495) __mptcp_destroy_sock (net/mptcp/protocol.c:2886) __mptcp_close (net/mptcp/protocol.c:2959) mptcp_close (net/mptcp/protocol.c:2974) inet_release (net/ipv4/af_inet.c:432) __sock_release (net/socket.c:651) sock_close (net/socket.c:1367) __fput (fs/file_table.c:320) task_work_run (kernel/task_work.c:181 (discriminator 1)) exit_to_user_mode_prepare (include/linux/resume_user_mode.h:49) syscall_exit_to_user_mode (kernel/entry/common.c:130) do_syscall_64 (arch/x86/entry/common.c:87) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sk_lock-AF_INET); lock((work_completion)(&msk->work)); lock(sk_lock-AF_INET); lock((work_completion)(&msk->work)); *** DEADLOCK *** The report is actually a false positive, since the only existing lock nesting is the msk socket lock acquired by the mptcp work. cancel_work_sync() is invoked without the relevant socket lock being held, but under a different (the msk listener) socket lock. We could silence the splat adding a per workqueue dynamic lockdep key, but that looks overkill. Instead just tell lockdep the msk socket lock is not held around cancel_work_sync(). Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/322 Fixes: 30e51b923e43 ("mptcp: fix unreleased socket in accept queue") Reported-by: Matthieu Baerts Reviewed-by: Mat Martineau Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mptcp: use proper req destructor for IPv6

2023-01-07T10:15:48+00:00

commit d3295fee3c756ece33ac0d935e172e68c0a4161b upstream. Before, only the destructor from TCP request sock in IPv4 was called even if the subflow was IPv6. It is important to use the right destructor to avoid memory leaks with some advanced IPv6 features, e.g. when the request socks contain specific IPv6 options. Fixes: 79c0949e9a09 ("mptcp: Add key generation and token tree") Reviewed-by: Mat Martineau Cc: stable@vger.kernel.org Signed-off-by: Matthieu Baerts Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

mptcp: dedicated request sock for subflow in v6

2023-01-07T10:15:48+00:00

commit 34b21d1ddc8ace77a8fa35c1b1e06377209e0dae upstream. tcp_request_sock_ops structure is specific to IPv4. It should then not be used with MPTCP subflows on top of IPv6. For example, it contains the 'family' field, initialised to AF_INET. This 'family' field is used by TCP FastOpen code to generate the cookie but also by TCP Metrics, SELinux and SYN Cookies. Using the wrong family will not lead to crashes but displaying/using/checking wrong things. Note that 'send_reset' callback from request_sock_ops structure is used in some error paths. It is then also important to use the correct one for IPv4 or IPv6. The slab name can also be different in IPv4 and IPv6, it will be used when printing some log messages. The slab pointer will anyway be the same because the object size is the same for both v4 and v6. A BUILD_BUG_ON() has also been added to make sure this size is the same. Fixes: cec37a6e41aa ("mptcp: Handle MP_CAPABLE options for outgoing connections") Reviewed-by: Mat Martineau Cc: stable@vger.kernel.org Signed-off-by: Matthieu Baerts Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

mptcp: remove MPTCP 'ifdef' in TCP SYN cookies

2023-01-07T10:15:48+00:00

commit 3fff88186f047627bb128d65155f42517f8e448f upstream. To ease the maintenance, it is often recommended to avoid having #ifdef preprocessor conditions. Here the section related to CONFIG_MPTCP was quite short but the next commit needs to add more code around. It is then cleaner to move specific MPTCP code to functions located in net/mptcp directory. Now that mptcp_subflow_request_sock_ops structure can be static, it can also be marked as "read only after init". Suggested-by: Paolo Abeni Reviewed-by: Mat Martineau Cc: stable@vger.kernel.org Signed-off-by: Matthieu Baerts Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

mptcp: netlink: fix some error return code

2023-01-07T10:15:48+00:00

commit e0fe1123ab2b07d2cd5475660bd0b4e6993ffaa7 upstream. Fix to return negative error code -EINVAL from some error handling case instead of 0, as done elsewhere in those functions. Fixes: 9ab4807c84a4 ("mptcp: netlink: Add MPTCP_PM_CMD_ANNOUNCE") Fixes: 702c2f646d42 ("mptcp: netlink: allow userspace-driven subflow establishment") Cc: stable@vger.kernel.org Reviewed-by: Matthieu Baerts Signed-off-by: Wei Yongjun Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

mptcp: fix sleep in atomic at close time

2022-12-08T10:30:17+00:00

[ Upstream commit b4f166651d03b5484fa179817ba8ad4899a5a6ac ] Matt reported a splat at msk close time: BUG: sleeping function called from invalid context at net/mptcp/protocol.c:2877 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 155, name: packetdrill preempt_count: 201, expected: 0 RCU nest depth: 0, expected: 0 4 locks held by packetdrill/155: #0: ffff888001536990 (&sb->s_type->i_mutex_key#6){+.+.}-{3:3}, at: __sock_release (net/socket.c:650) #1: ffff88800b498130 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close (net/mptcp/protocol.c:2973) #2: ffff88800b49a130 (sk_lock-AF_INET/1){+.+.}-{0:0}, at: __mptcp_close_ssk (net/mptcp/protocol.c:2363) #3: ffff88800b49a0b0 (slock-AF_INET){+...}-{2:2}, at: __lock_sock_fast (include/net/sock.h:1820) Preemption disabled at: 0x0 CPU: 1 PID: 155 Comm: packetdrill Not tainted 6.1.0-rc5 #365 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) __might_resched.cold (kernel/sched/core.c:9891) __mptcp_destroy_sock (include/linux/kernel.h:110) __mptcp_close (net/mptcp/protocol.c:2959) mptcp_subflow_queue_clean (include/net/sock.h:1777) __mptcp_close_ssk (net/mptcp/protocol.c:2363) mptcp_destroy_common (net/mptcp/protocol.c:3170) mptcp_destroy (include/net/sock.h:1495) __mptcp_destroy_sock (net/mptcp/protocol.c:2886) __mptcp_close (net/mptcp/protocol.c:2959) mptcp_close (net/mptcp/protocol.c:2974) inet_release (net/ipv4/af_inet.c:432) __sock_release (net/socket.c:651) sock_close (net/socket.c:1367) __fput (fs/file_table.c:320) task_work_run (kernel/task_work.c:181 (discriminator 1)) exit_to_user_mode_prepare (include/linux/resume_user_mode.h:49) syscall_exit_to_user_mode (kernel/entry/common.c:130) do_syscall_64 (arch/x86/entry/common.c:87) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) We can't call mptcp_close under the 'fast' socket lock variant, replace it with a sock_lock_nested() as the relevant code is already under the listening msk socket lock protection. Reported-by: Matthieu Baerts Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/316 Fixes: 30e51b923e43 ("mptcp: fix unreleased socket in accept queue") Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts Signed-off-by: Matthieu Baerts Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mptcp: don't orphan ssk in mptcp_close()

2022-12-08T10:30:17+00:00

[ Upstream commit fe94800184f22d4778628f1321dce5acb7513d84 ] All of the subflows of a msk will be orphaned in mptcp_close(), which means the subflows are in DEAD state. After then, DATA_FIN will be sent, and the other side will response with a DATA_ACK for this DATA_FIN. However, if the other side still has pending data, the data that received on these subflows will not be passed to the msk, as they are DEAD and subflow_data_ready() will not be called in tcp_data_ready(). Therefore, these data can't be acked, and they will be retransmitted again and again, until timeout. Fix this by setting ssk->sk_socket and ssk->sk_wq to 'NULL', instead of orphaning the subflows in __mptcp_close(), as Paolo suggested. Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close") Reviewed-by: Biao Jiang Reviewed-by: Mengen Sun Signed-off-by: Menglong Dong Reviewed-by: Paolo Abeni Signed-off-by: Matthieu Baerts Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mptcp: set msk local address earlier

2022-11-03T15:00:31+00:00

[ Upstream commit e72e4032637f4646554794ac28a3abecc6c2416d ] The mptcp_pm_nl_get_local_id() code assumes that the msk local address is available at that point. For passive sockets, we initialize such address at accept() time. Depending on the running configuration and the user-space timing, a passive MPJ subflow can join the msk socket before accept() completes. In such case, the PM assigns a wrong local id to the MPJ subflow and later PM netlink operations will end-up touching the wrong/unexpected subflow. All the above causes sporadic self-tests failures, especially when the host is heavy loaded. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/308 Fixes: 01cacb00b35c ("mptcp: add netlink-based PM") Fixes: d045b9eb95a9 ("mptcp: introduce implicit endpoints") Reviewed-by: Mat Martineau Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

mptcp: fix unreleased socket in accept queue

2022-09-29T02:05:21+00:00

The mptcp socket and its subflow sockets in accept queue can't be released after the process exit. While the release of a mptcp socket in listening state, the corresponding tcp socket will be released too. Meanwhile, the tcp socket in the unaccept queue will be released too. However, only init subflow is in the unaccept queue, and the joined subflow is not in the unaccept queue, which makes the joined subflow won't be released, and therefore the corresponding unaccepted mptcp socket will not be released to. This can be reproduced easily with following steps: 1. create 2 namespace and veth: $ ip netns add mptcp-client $ ip netns add mptcp-server $ sysctl -w net.ipv4.conf.all.rp_filter=0 $ ip netns exec mptcp-client sysctl -w net.mptcp.enabled=1 $ ip netns exec mptcp-server sysctl -w net.mptcp.enabled=1 $ ip link add red-client netns mptcp-client type veth peer red-server \ netns mptcp-server $ ip -n mptcp-server address add 10.0.0.1/24 dev red-server $ ip -n mptcp-server address add 192.168.0.1/24 dev red-server $ ip -n mptcp-client address add 10.0.0.2/24 dev red-client $ ip -n mptcp-client address add 192.168.0.2/24 dev red-client $ ip -n mptcp-server link set red-server up $ ip -n mptcp-client link set red-client up 2. configure the endpoint and limit for client and server: $ ip -n mptcp-server mptcp endpoint flush $ ip -n mptcp-server mptcp limits set subflow 2 add_addr_accepted 2 $ ip -n mptcp-client mptcp endpoint flush $ ip -n mptcp-client mptcp limits set subflow 2 add_addr_accepted 2 $ ip -n mptcp-client mptcp endpoint add 192.168.0.2 dev red-client id \ 1 subflow 3. listen and accept on a port, such as 9999. The nc command we used here is modified, which makes it use mptcp protocol by default. $ ip netns exec mptcp-server nc -l -k -p 9999 4. open another *two* terminal and use each of them to connect to the server with the following command: $ ip netns exec mptcp-client nc 10.0.0.1 9999 Input something after connect to trigger the connection of the second subflow. So that there are two established mptcp connections, with the second one still unaccepted. 5. exit all the nc command, and check the tcp socket in server namespace. And you will find that there is one tcp socket in CLOSE_WAIT state and can't release forever. Fix this by closing all of the unaccepted mptcp socket in mptcp_subflow_queue_clean() with __mptcp_close(). Now, we can ensure that all unaccepted mptcp sockets will be cleaned by __mptcp_close() before they are released, so mptcp_sock_destruct(), which is used to clean the unaccepted mptcp socket, is not needed anymore. The selftests for mptcp is ran for this commit, and no new failures. Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Fixes: 6aeed9045071 ("mptcp: fix race on unaccepted mptcp sockets") Cc: stable@vger.kernel.org Reviewed-by: Jiang Biao Reviewed-by: Mengen Sun Acked-by: Paolo Abeni Signed-off-by: Menglong Dong Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski

mptcp: factor out __mptcp_close() without socket lock

2022-09-29T02:05:21+00:00

Factor out __mptcp_close() from mptcp_close(). The caller of __mptcp_close() should hold the socket lock, and cancel mptcp work when __mptcp_close() returns true. This function will be used in the next commit. Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Fixes: 6aeed9045071 ("mptcp: fix race on unaccepted mptcp sockets") Cc: stable@vger.kernel.org Reviewed-by: Jiang Biao Reviewed-by: Mengen Sun Acked-by: Paolo Abeni Signed-off-by: Menglong Dong Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski