kernel/net/rxrpc/call_object.c, branch linux-5.1.y

rxrpc: Fix net namespace cleanup

2019-04-30T14:50:50Z

In rxrpc_destroy_all_calls(), there are two phases: (1) make sure the ->calls list is empty, emitting error messages if not, and (2) wait for the RCU cleanup to happen on outstanding calls (ie. ->nr_calls becomes 0). To avoid taking the call_lock, the function prechecks ->calls and if empty, it returns to avoid taking the lock - this is wrong, however: it still needs to go and do the second phase and wait for ->nr_calls to become 0. Without this, the rxrpc_net struct may get deallocated before we get to the RCU cleanup for the last calls. This can lead to: Slab corruption (Not tainted): kmalloc-16k start=ffff88802b178000, len=16384 050: 6b 6b 6b 6b 6b 6b 6b 6b 61 6b 6b 6b 6b 6b 6b 6b kkkkkkkkakkkkkkk Note the "61" at offset 0x58. This corresponds to the ->nr_calls member of struct rxrpc_net (which is >9k in size, and thus allocated out of the 16k slab). Fix this by flipping the condition on the if-statement, putting the locked section inside the if-body and dropping the return from there. The function will then always go on to wait for the RCU cleanup on outstanding calls. Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Signed-off-by: David Howells Signed-off-by: David S. Miller

Revert "rxrpc: Allow failed client calls to be retried"

2019-01-16T05:33:36Z

The changes introduced to allow rxrpc calls to be retried creates an issue when it comes to refcounting afs_call structs. The problem is that when rxrpc_send_data() queues the last packet for an asynchronous call, the following sequence can occur: (1) The notify_end_tx callback is invoked which causes the state in the afs_call to be changed from AFS_CALL_CL_REQUESTING or AFS_CALL_SV_REPLYING. (2) afs_deliver_to_call() can then process event notifications from rxrpc on the async_work queue. (3) Delivery of events, such as an abort from the server, can cause the afs_call state to be changed to AFS_CALL_COMPLETE on async_work. (4) For an asynchronous call, afs_process_async_call() notes that the call is complete and tried to clean up all the refs on async_work. (5) rxrpc_send_data() might return the amount of data transferred (success) or an error - which could in turn reflect a local error or a received error. Synchronising the clean up after rxrpc_kernel_send_data() returns an error with the asynchronous cleanup is then tricky to get right. Mostly revert commit c038a58ccfd6704d4d7d60ed3d6a0fca13cf13a4. The two API functions the original commit added aren't currently used. This makes rxrpc_kernel_send_data() always return successfully if it queued the data it was given. Note that this doesn't affect synchronous calls since their Rx notification function merely pokes a wait queue and does not refcounting. The asynchronous call notification function *has* to do refcounting and pass a ref over the work item to avoid the need to sync the workqueue in call cleanup. Signed-off-by: David Howells Signed-off-by: David S. Miller

rxrpc: Fix the packet reception routine

2018-10-08T21:42:04Z

The rxrpc_input_packet() function and its call tree was built around the assumption that data_ready() handler called from UDP to inform a kernel service that there is data to be had was non-reentrant. This means that certain locking could be dispensed with. This, however, turns out not to be the case with a multi-queue network card that can deliver packets to multiple cpus simultaneously. Each of those cpus can be in the rxrpc_input_packet() function at the same time. Fix by adding or changing some structure members: (1) Add peer->rtt_input_lock to serialise access to the RTT buffer. (2) Make conn->service_id into a 32-bit variable so that it can be cmpxchg'd on all arches. (3) Add call->input_lock to serialise access to the Rx/Tx state. Note that although the Rx and Tx states are (almost) entirely separate, there's no point completing the separation and having separate locks since it's a bi-phasal RPC protocol rather than a bi-direction streaming protocol. Data transmission and data reception do not take place simultaneously on any particular call. and making the following functional changes: (1) In rxrpc_input_data(), hold call->input_lock around the core to prevent simultaneous producing of packets into the Rx ring and updating of tracking state for a particular call. (2) In rxrpc_input_ping_response(), only read call->ping_serial once, and check it before checking RXRPC_CALL_PINGING as that's a cheaper test. The bit test and bit clear can then be combined. No further locking is needed here. (3) In rxrpc_input_ack(), take call->input_lock after we've parsed much of the ACK packet. The superseded ACK check is then done both before and after the lock is taken. The handing of ackinfo data is split, parsing before the lock is taken and processing with it held. This is keyed on rxMTU being non-zero. Congestion management is also done within the locked section. (4) In rxrpc_input_ackall(), take call->input_lock around the Tx window rotation. The ACKALL packet carries no information and is only really useful after all packets have been transmitted since it's imprecise. (5) In rxrpc_input_implicit_end_call(), we use rx->incoming_lock to prevent calls being simultaneously implicitly ended on two cpus and also to prevent any races with incoming call setup. (6) In rxrpc_input_packet(), use cmpxchg() to effect the service upgrade on a connection. It is only permitted to happen once for a connection. (7) In rxrpc_new_incoming_call(), we have to recheck the routing inside rx->incoming_lock to see if someone else set up the call, connection or peer whilst we were getting there. We can't trust the values from the earlier routing check unless we pin refs on them - which we want to avoid. Further, we need to allow for an incoming call to have its state changed on another CPU between us making it live and us adjusting it because the conn is now in the RXRPC_CONN_SERVICE state. (8) In rxrpc_peer_add_rtt(), take peer->rtt_input_lock around the access to the RTT buffer. Don't need to lock around setting peer->rtt. For reference, the inventory of state-accessing or state-altering functions used by the packet input procedure is: > rxrpc_input_packet() * PACKET CHECKING * ROUTING > rxrpc_post_packet_to_local() > rxrpc_find_connection_rcu() - uses RCU > rxrpc_lookup_peer_rcu() - uses RCU > rxrpc_find_service_conn_rcu() - uses RCU > idr_find() - uses RCU * CONNECTION-LEVEL PROCESSING - Service upgrade - Can only happen once per conn ! Changed to use cmpxchg > rxrpc_post_packet_to_conn() - Setting conn->hi_serial - Probably safe not using locks - Maybe use cmpxchg * CALL-LEVEL PROCESSING > Old-call checking > rxrpc_input_implicit_end_call() > rxrpc_call_completed() > rxrpc_queue_call() ! Need to take rx->incoming_lock > __rxrpc_disconnect_call() > rxrpc_notify_socket() > rxrpc_new_incoming_call() - Uses rx->incoming_lock for the entire process - Might be able to drop this earlier in favour of the call lock > rxrpc_incoming_call() ! Conflicts with rxrpc_input_implicit_end_call() > rxrpc_send_ping() - Don't need locks to check rtt state > rxrpc_propose_ACK * PACKET DISTRIBUTION > rxrpc_input_call_packet() > rxrpc_input_data() * QUEUE DATA PACKET ON CALL > rxrpc_reduce_call_timer() - Uses timer_reduce() ! Needs call->input_lock() > rxrpc_receiving_reply() ! Needs locking around ack state > rxrpc_rotate_tx_window() > rxrpc_end_tx_phase() > rxrpc_proto_abort() > rxrpc_input_dup_data() - Fills the Rx buffer - rxrpc_propose_ACK() - rxrpc_notify_socket() > rxrpc_input_ack() * APPLY ACK PACKET TO CALL AND DISCARD PACKET > rxrpc_input_ping_response() - Probably doesn't need any extra locking ! Need READ_ONCE() on call->ping_serial > rxrpc_input_check_for_lost_ack() - Takes call->lock to consult Tx buffer > rxrpc_peer_add_rtt() ! Needs to take a lock (peer->rtt_input_lock) ! Could perhaps manage with cmpxchg() and xadd() instead > rxrpc_input_requested_ack - Consults Tx buffer ! Probably needs a lock > rxrpc_peer_add_rtt() > rxrpc_propose_ack() > rxrpc_input_ackinfo() - Changes call->tx_winsize ! Use cmpxchg to handle change ! Should perhaps track serial number - Uses peer->lock to record MTU specification changes > rxrpc_proto_abort() ! Need to take call->input_lock > rxrpc_rotate_tx_window() > rxrpc_end_tx_phase() > rxrpc_input_soft_acks() - Consults the Tx buffer > rxrpc_congestion_management() - Modifies the Tx annotations ! Needs call->input_lock() > rxrpc_queue_call() > rxrpc_input_abort() * APPLY ABORT PACKET TO CALL AND DISCARD PACKET > rxrpc_set_call_completion() > rxrpc_notify_socket() > rxrpc_input_ackall() * APPLY ACKALL PACKET TO CALL AND DISCARD PACKET ! Need to take call->input_lock > rxrpc_rotate_tx_window() > rxrpc_end_tx_phase() > rxrpc_reject_packet() There are some functions used by the above that queue the packet, after which the procedure is terminated: - rxrpc_post_packet_to_local() - local->event_queue is an sk_buff_head - local->processor is a work_struct - rxrpc_post_packet_to_conn() - conn->rx_queue is an sk_buff_head - conn->processor is a work_struct - rxrpc_reject_packet() - local->reject_queue is an sk_buff_head - local->processor is a work_struct And some that offload processing to process context: - rxrpc_notify_socket() - Uses RCU lock - Uses call->notify_lock to call call->notify_rx - Uses call->recvmsg_lock to queue recvmsg side - rxrpc_queue_call() - call->processor is a work_struct - rxrpc_propose_ACK() - Uses call->lock to wrap __rxrpc_propose_ACK() And a bunch that complete a call, all of which use call->state_lock to protect the call state: - rxrpc_call_completed() - rxrpc_set_call_completion() - rxrpc_abort_call() - rxrpc_proto_abort() - Also uses rxrpc_queue_call() Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by: David Howells

rxrpc: Fix some missed refs to init_net

2018-10-05T13:21:59Z

Fix some refs to init_net that should've been changed to the appropriate network namespace. Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Signed-off-by: David Howells Acked-by: Paolo Abeni

rxrpc: Fix error distribution

2018-09-28T09:33:17Z

Fix error distribution by immediately delivering the errors to all the affected calls rather than deferring them to a worker thread. The problem with the latter is that retries and things can happen in the meantime when we want to stop that sooner. To this end: (1) Stop the error distributor from removing calls from the error_targets list so that peer->lock isn't needed to synchronise against other adds and removals. (2) Require the peer's error_targets list to be accessed with RCU, thereby avoiding the need to take peer->lock over distribution. (3) Don't attempt to affect a call's state if it is already marked complete. Signed-off-by: David Howells

atomics/treewide: Rename __atomic_add_unless() => atomic_fetch_add_unless()

2018-06-21T12:22:32Z

While __atomic_add_unless() was originally intended as a building-block for atomic_add_unless(), it's now used in a number of places around the kernel. It's the only common atomic operation named __atomic*(), rather than atomic_*(), and for consistency it would be better named atomic_fetch_add_unless(). This lack of consistency is slightly confusing, and gets in the way of scripting atomics. Given that, let's clean things up and promote it to an official part of the atomics API, in the form of atomic_fetch_add_unless(). This patch converts definitions and invocations over to the new name, including the instrumented version, using the following script: ---- git grep -w __atomic_add_unless | while read line; do sed -i '{s/\<__atomic_add_unless\>/atomic_fetch_add_unless/}' "${line%%:*}"; done git grep -w __arch_atomic_add_unless | while read line; do sed -i '{s/\<__arch_atomic_add_unless\>/arch_atomic_fetch_add_unless/}' "${line%%:*}"; done ---- Note that we do not have atomic{64,_long}_fetch_add_unless(), which will be introduced by later patches. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Reviewed-by: Will Deacon Acked-by: Geert Uytterhoeven Acked-by: Peter Zijlstra (Intel) Acked-by: Palmer Dabbelt Cc: Boqun Feng Cc: Linus Torvalds Cc: Thomas Gleixner Link: https://lore.kernel.org/lkml/20180621121321.4761-2-mark.rutland@arm.com Signed-off-by: Ingo Molnar

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

2018-04-03T21:04:18Z

Pull networking updates from David Miller: 1) Support offloading wireless authentication to userspace via NL80211_CMD_EXTERNAL_AUTH, from Srinivas Dasari. 2) A lot of work on network namespace setup/teardown from Kirill Tkhai. Setup and cleanup of namespaces now all run asynchronously and thus performance is significantly increased. 3) Add rx/tx timestamping support to mv88e6xxx driver, from Brandon Streiff. 4) Support zerocopy on RDS sockets, from Sowmini Varadhan. 5) Use denser instruction encoding in x86 eBPF JIT, from Daniel Borkmann. 6) Support hw offload of vlan filtering in mvpp2 dreiver, from Maxime Chevallier. 7) Support grafting of child qdiscs in mlxsw driver, from Nogah Frankel. 8) Add packet forwarding tests to selftests, from Ido Schimmel. 9) Deal with sub-optimal GSO packets better in BBR congestion control, from Eric Dumazet. 10) Support 5-tuple hashing in ipv6 multipath routing, from David Ahern. 11) Add path MTU tests to selftests, from Stefano Brivio. 12) Various bits of IPSEC offloading support for mlx5, from Aviad Yehezkel, Yossi Kuperman, and Saeed Mahameed. 13) Support RSS spreading on ntuple filters in SFC driver, from Edward Cree. 14) Lots of sockmap work from John Fastabend. Applications can use eBPF to filter sendmsg and sendpage operations. 15) In-kernel receive TLS support, from Dave Watson. 16) Add XDP support to ixgbevf, this is significant because it should allow optimized XDP usage in various cloud environments. From Tony Nguyen. 17) Add new Intel E800 series "ice" ethernet driver, from Anirudh Venkataramanan et al. 18) IP fragmentation match offload support in nfp driver, from Pieter Jansen van Vuuren. 19) Support XDP redirect in i40e driver, from Björn Töpel. 20) Add BPF_RAW_TRACEPOINT program type for accessing the arguments of tracepoints in their raw form, from Alexei Starovoitov. 21) Lots of striding RQ improvements to mlx5 driver with many performance improvements, from Tariq Toukan. 22) Use rhashtable for inet frag reassembly, from Eric Dumazet. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1678 commits) net: mvneta: improve suspend/resume net: mvneta: split rxq/txq init and txq deinit into SW and HW parts ipv6: frags: fix /proc/sys/net/ipv6/ip6frag_low_thresh net: bgmac: Fix endian access in bgmac_dma_tx_ring_free() net: bgmac: Correctly annotate register space route: check sysctl_fib_multipath_use_neigh earlier than hash fix typo in command value in drivers/net/phy/mdio-bitbang. sky2: Increase D3 delay to sky2 stops working after suspend net/mlx5e: Set EQE based as default TX interrupt moderation mode ibmvnic: Disable irqs before exiting reset from closed state net: sched: do not emit messages while holding spinlock vlan: also check phy_driver ts_info for vlan's real device Bluetooth: Mark expected switch fall-throughs Bluetooth: Set HCI_QUIRK_SIMULTANEOUS_DISCOVERY for BTUSB_QCA_ROME Bluetooth: btrsi: remove unused including Bluetooth: hci_bcm: Remove DMI quirk for the MINIX Z83-4 sh_eth: kill useless check in __sh_eth_get_regs() sh_eth: add sh_eth_cpu_data::no_xdfar flag ipv6: factorize sk_wmem_alloc updates done by __ip6_append_data() ipv4: factorize sk_wmem_alloc updates done by __ip_append_data() ...

rxrpc: Fix potential call vs socket/net destruction race

2018-03-30T20:05:23Z

rxrpc_call structs don't pin sockets or network namespaces, but may attempt to access both after their refcount reaches 0 so that they can detach themselves from the network namespace. However, there's no guarantee that the socket still exists at this point (so sock_net(&call->socket->sk) may be invalid) and the namespace may have gone away if the call isn't pinning a peer. Fix this by (a) carrying a net pointer in the rxrpc_call struct and (b) waiting for all calls to be destroyed when the network namespace goes away. This was detected by checker: net/rxrpc/call_object.c:634:57: warning: incorrect type in argument 1 (different address spaces) net/rxrpc/call_object.c:634:57: expected struct sock const *sk net/rxrpc/call_object.c:634:57: got struct sock [noderef] * Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Signed-off-by: David Howells

rxrpc: Fix checker warnings and errors

2018-03-30T20:05:17Z

Fix various issues detected by checker. Errors: (*) rxrpc_discard_prealloc() should be using rcu_assign_pointer to set call->socket. Warnings: (*) rxrpc_service_connection_reaper() should be passing NULL rather than 0 to trace_rxrpc_conn() as the where argument. (*) rxrpc_disconnect_client_call() should get its net pointer via the call->conn rather than call->sock to avoid a warning about accessing an RCU pointer without protection. (*) Proc seq start/stop functions need annotation as they pass locks between the functions. False positives: (*) Checker doesn't correctly handle of seq-retry lock context balance in rxrpc_find_service_conn_rcu(). (*) Checker thinks execution may proceed past the BUG() in rxrpc_publish_service_conn(). (*) Variable length array warnings from SKCIPHER_REQUEST_ON_STACK() in rxkad.c. Signed-off-by: David Howells

rxrpc, afs: Use debug_ids rather than pointers in traces

2018-03-27T22:03:00Z

In rxrpc and afs, use the debug_ids that are monotonically allocated to various objects as they're allocated rather than pointers as kernel pointers are now hashed making them less useful. Further, the debug ids aren't reused anywhere nearly as quickly. In addition, allow kernel services that use rxrpc, such as afs, to take numbers from the rxrpc counter, assign them to their own call struct and pass them in to rxrpc for both client and service calls so that the trace lines for each will have the same ID tag. Signed-off-by: David Howells