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* tipc: fix cleanup at module unloadParthasarathy Bhuvaragan2017-01-241-3/+1
| | | | | | | | | | | | | | In tipc_server_stop(), we iterate over the connections with limiting factor as server's idr_in_use. We ignore the fact that this variable is decremented in tipc_close_conn(), leading to premature exit. In this commit, we iterate until the we have no connections left. Acked-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Tested-by: John Thompson <thompa.atl@gmail.com> Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: ignore requests when the connection state is not CONNECTEDParthasarathy Bhuvaragan2017-01-241-6/+7
| | | | | | | | | | | | | | | In tipc_conn_sendmsg(), we first queue the request to the outqueue followed by the connection state check. If the connection is not connected, we should not queue this message. In this commit, we reject the messages if the connection state is not CF_CONNECTED. Acked-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Tested-by: John Thompson <thompa.atl@gmail.com> Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix nametbl_lock soft lockup at module exitParthasarathy Bhuvaragan2017-01-241-11/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 333f796235a527 ("tipc: fix a race condition leading to subscriber refcnt bug") reveals a soft lockup while acquiring nametbl_lock. Before commit 333f796235a527, we call tipc_conn_shutdown() from tipc_close_conn() in the context of tipc_topsrv_stop(). In that context, we are allowed to grab the nametbl_lock. Commit 333f796235a527, moved tipc_conn_release (renamed from tipc_conn_shutdown) to the connection refcount cleanup. This allows either tipc_nametbl_withdraw() or tipc_topsrv_stop() to the cleanup. Since tipc_exit_net() first calls tipc_topsrv_stop() and then tipc_nametble_withdraw() increases the chances for the later to perform the connection cleanup. The soft lockup occurs in the call chain of tipc_nametbl_withdraw(), when it performs the tipc_conn_kref_release() as it tries to grab nametbl_lock again while holding it already. tipc_nametbl_withdraw() grabs nametbl_lock tipc_nametbl_remove_publ() tipc_subscrp_report_overlap() tipc_subscrp_send_event() tipc_conn_sendmsg() << if (con->flags != CF_CONNECTED) we do conn_put(), triggering the cleanup as refcount=0. >> tipc_conn_kref_release tipc_sock_release tipc_conn_release tipc_subscrb_delete tipc_subscrp_delete tipc_nametbl_unsubscribe << Soft Lockup >> The previous changes in this series fixes the race conditions fixed by commit 333f796235a527. Hence we can now revert the commit. Fixes: 333f796235a52727 ("tipc: fix a race condition leading to subscriber refcnt bug") Reported-and-Tested-by: John Thompson <thompa.atl@gmail.com> Acked-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix connection refcount errorParthasarathy Bhuvaragan2017-01-241-9/+10
| | | | | | | | | | | | | | | | | | | | | | | Until now, the generic server framework maintains the connection id's per subscriber in server's conn_idr. At tipc_close_conn, we remove the connection id from the server list, but the connection is valid until we call the refcount cleanup. Hence we have a window where the server allocates the same connection to an new subscriber leading to inconsistent reference count. We have another refcount warning we grab the refcount in tipc_conn_lookup() for connections with flag with CF_CONNECTED not set. This usually occurs at shutdown when the we stop the topology server and withdraw TIPC_CFG_SRV publication thereby triggering a withdraw message to subscribers. In this commit, we: 1. remove the connection from the server list at recount cleanup. 2. grab the refcount for a connection only if CF_CONNECTED is set. Tested-by: John Thompson <thompa.atl@gmail.com> Acked-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: Use kmemdup instead of kmalloc and memcpyAmitoj Kaur Chawla2016-06-271-2/+1
| | | | | | | | | | | | | | | | | | | | Replace calls to kmalloc followed by a memcpy with a direct call to kmemdup. The Coccinelle semantic patch used to make this change is as follows: @@ expression from,to,size,flag; statement S; @@ - to = \(kmalloc\|kzalloc\)(size,flag); + to = kmemdup(from,size,flag); if (to==NULL || ...) S - memcpy(to, from, size); Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: block BH in TCP callbacksEric Dumazet2016-05-191-4/+4
| | | | | | | | | | | | | | TCP stack can now run from process context. Use read_lock_bh(&sk->sk_callback_lock) variant to restore previous assumption. Fixes: 5413d1babe8f ("net: do not block BH while processing socket backlog") Fixes: d41a69f1d390 ("tcp: make tcp_sendmsg() aware of socket backlog") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jon Maloy <jon.maloy@ericsson.com> Cc: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix a race condition leading to subscriber refcnt bugParthasarathy Bhuvaragan2016-04-141-6/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Until now, the requests sent to topology server are queued to a workqueue by the generic server framework. These messages are processed by worker threads and trigger the registered callbacks. To reduce latency on uniprocessor systems, explicit rescheduling is performed using cond_resched() after MAX_RECV_MSG_COUNT(25) messages. This implementation on SMP systems leads to an subscriber refcnt error as described below: When a worker thread yields by calling cond_resched() in a SMP system, a new worker is created on another CPU to process the pending workitem. Sometimes the sleeping thread wakes up before the new thread finishes execution. This breaks the assumption on ordering and being single threaded. The fault is more frequent when MAX_RECV_MSG_COUNT is lowered. If the first thread was processing subscription create and the second thread processing close(), the close request will free the subscriber and the create request oops as follows: [31.224137] WARNING: CPU: 2 PID: 266 at include/linux/kref.h:46 tipc_subscrb_rcv_cb+0x317/0x380 [tipc] [31.228143] CPU: 2 PID: 266 Comm: kworker/u8:1 Not tainted 4.5.0+ #97 [31.228377] Workqueue: tipc_rcv tipc_recv_work [tipc] [...] [31.228377] Call Trace: [31.228377] [<ffffffff812fbb6b>] dump_stack+0x4d/0x72 [31.228377] [<ffffffff8105a311>] __warn+0xd1/0xf0 [31.228377] [<ffffffff8105a3fd>] warn_slowpath_null+0x1d/0x20 [31.228377] [<ffffffffa0098067>] tipc_subscrb_rcv_cb+0x317/0x380 [tipc] [31.228377] [<ffffffffa00a4984>] tipc_receive_from_sock+0xd4/0x130 [tipc] [31.228377] [<ffffffffa00a439b>] tipc_recv_work+0x2b/0x50 [tipc] [31.228377] [<ffffffff81071925>] process_one_work+0x145/0x3d0 [31.246554] ---[ end trace c3882c9baa05a4fd ]--- [31.248327] BUG: spinlock bad magic on CPU#2, kworker/u8:1/266 [31.249119] BUG: unable to handle kernel NULL pointer dereference at 0000000000000428 [31.249323] IP: [<ffffffff81099d0c>] spin_dump+0x5c/0xe0 [31.249323] PGD 0 [31.249323] Oops: 0000 [#1] SMP In this commit, we - rename tipc_conn_shutdown() to tipc_conn_release(). - move connection release callback execution from tipc_close_conn() to a new function tipc_sock_release(), which is executed before we free the connection. Thus we release the subscriber during connection release procedure rather than connection shutdown procedure. Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: use alloc_ordered_workqueue() instead of WQ_UNBOUND w/ max_active = 1Parthasarathy Bhuvaragan2016-02-061-2/+2
| | | | | | | | | | | | | | | | Until now, tipc_rcv and tipc_send workqueues in server are allocated with parameters WQ_UNBOUND & max_active = 1. This parameters passed to this function makes it equivalent to alloc_ordered_workqueue(). The later form is more explicit and can inherit future ordered_workqueue changes. In this commit we replace alloc_workqueue() with more readable alloc_ordered_workqueue(). Acked-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: use sock_create_kern interface to create kernel socketYing Xue2015-05-141-1/+1
| | | | | | | | | After commit eeb1bd5c40ed ("net: Add a struct net parameter to sock_create_kern"), we should use sock_create_kern() to create kernel socket as the interface doesn't reference count struct net any more. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: deal with return value of tipc_conn_new callbackYing Xue2015-05-041-0/+4
| | | | | | | | | Once tipc_conn_new() returns NULL, the connection should be shut down immediately, otherwise, oops may happen due to the NULL pointer. Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix topology server broken issueYing Xue2015-04-231-6/+3
| | | | | | | | | | | | | | | | | | | | | | | When a new topology server is launched in a new namespace, its listening socket is inserted into the "init ns" namespace's socket hash table rather than the one owned by the new namespace. Although the socket's namespace is forcedly changed to the new namespace later, the socket is still stored in the socket hash table of "init ns" namespace. When a client created in the new namespace connects its own topology server, the connection is failed as its server's socket could not be found from its own namespace's socket table. If __sock_create() instead of original sock_create_kern() is used to create the server's socket through specifying an expected namesapce, the socket will be inserted into the specified namespace's socket table, thereby avoiding to the topology server broken issue. Fixes: 76100a8a64bc ("tipc: fix netns refcnt leak") Reported-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: withdraw tipc topology server name when namespace is deletedYing Xue2015-03-181-0/+3
| | | | | | | | | | | | | | | | | | The TIPC topology server is a per namespace service associated with the tipc name {1, 1}. When a namespace is deleted, that name must be withdrawn before we call sk_release_kernel because the kernel socket release is done in init_net and trying to withdraw a TIPC name published in another namespace will fail with an error as: [ 170.093264] Unable to remove local publication [ 170.093264] (type=1, lower=1, ref=2184244004, key=2184244005) We fix this by breaking the association between the topology server name and socket before calling sk_release_kernel. Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix netns refcnt leakYing Xue2015-03-181-6/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the TIPC module is loaded, we launch a topology server in kernel space, which in its turn is creating TIPC sockets for communication with topology server users. Because both the socket's creator and provider reside in the same module, it is necessary that the TIPC module's reference count remains zero after the server is started and the socket created; otherwise it becomes impossible to perform "rmmod" even on an idle module. Currently, we achieve this by defining a separate "tipc_proto_kern" protocol struct, that is used only for kernel space socket allocations. This structure has the "owner" field set to NULL, which restricts the module reference count from being be bumped when sk_alloc() for local sockets is called. Furthermore, we have defined three kernel-specific functions, tipc_sock_create_local(), tipc_sock_release_local() and tipc_sock_accept_local(), to avoid the module counter being modified when module local sockets are created or deleted. This has worked well until we introduced name space support. However, after name space support was introduced, we have observed that a reference count leak occurs, because the netns counter is not decremented in tipc_sock_delete_local(). This commit remedies this problem. But instead of just modifying tipc_sock_delete_local(), we eliminate the whole parallel socket handling infrastructure, and start using the regular sk_create_kern(), kernel_accept() and sk_release_kernel() calls. Since those functions manipulate the module counter, we must now compensate for that by explicitly decrementing the counter after module local sockets are created, and increment it just before calling sk_release_kernel(). Fixes: a62fbccecd62 ("tipc: make subscriber server support net namespace") Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reported-by: Cong Wang <cwang@twopensource.com> Tested-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: make subscriber server support net namespaceYing Xue2015-01-121-1/+1
| | | | | | | | | | | | | TIPC establishes one subscriber server which allows users to subscribe their interesting name service status. After tipc supports namespace, one dedicated tipc stack instance is created for each namespace, and each instance can be deemed as one independent TIPC node. As a result, subscriber server must be built for each namespace. Signed-off-by: Ying Xue <ying.xue@windriver.com> Tested-by: Tero Aho <Tero.Aho@coriant.com> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: name tipc name table support net namespaceYing Xue2015-01-121-1/+2
| | | | | | | | | | | | | | | | | | TIPC name table is used to store the mapping relationship between TIPC service name and socket port ID. When tipc supports namespace, it allows users to publish service names only owned by a certain namespace. Therefore, every namespace must have its private name table to prevent service names published to one namespace from being contaminated by other service names in another namespace. Therefore, The name table global variable (ie, nametbl) and its lock must be moved to tipc_net structure, and a parameter of namespace must be added for necessary functions so that they can obtain name table variable defined in tipc_net structure. Signed-off-by: Ying Xue <ying.xue@windriver.com> Tested-by: Tero Aho <Tero.Aho@coriant.com> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: cleanup core.c and core.h filesYing Xue2015-01-121-0/+1
| | | | | | | | | | | Only the works of initializing and shutting down tipc module are done in core.h and core.c files, so all stuffs which are not closely associated with the two tasks should be moved to appropriate places. Signed-off-by: Ying Xue <ying.xue@windriver.com> Tested-by: Tero Aho <Tero.Aho@coriant.com> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Fix use after free by removing length arg from sk_data_ready callbacks.David S. Miller2014-04-111-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix connection refcount leakYing Xue2014-03-061-2/+4
| | | | | | | | | | | | | | | | | | | When tipc_conn_sendmsg() calls tipc_conn_lookup() to query a connection instance, its reference count value is increased if it's found. But subsequently if it's found that the connection is closed, the work of sending message is not queued into its server send workqueue, and the connection reference count is not decreased. This will cause a reference count leak. To reproduce this problem, an application would need to open and closes topology server connections with high intensity. We fix this by immediately decrementing the connection reference count if a send fails due to the connection being closed. Signed-off-by: Ying Xue <ying.xue@windriver.com> Acked-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: allow connection shutdown callback to be invoked in advanceYing Xue2014-03-061-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently connection shutdown callback function is called when connection instance is released in tipc_conn_kref_release(), and receiving packets and sending packets are running in different threads. Even if connection is closed by the thread of receiving packets, its shutdown callback may not be called immediately as the connection reference count is non-zero at that moment. So, although the connection is shut down by the thread of receiving packets, the thread of sending packets doesn't know it. Before its shutdown callback is invoked to tell the sending thread its connection has been closed, the sending thread may deliver messages by tipc_conn_sendmsg(), this is why the following error information appears: "Sending subscription event failed, no memory" To eliminate it, allow connection shutdown callback function to be called before connection id is removed in tipc_close_conn(), which makes the sending thread know the truth in time that its socket is closed so that it doesn't send message to it. We also remove the "Sending XXX failed..." error reporting for topology and config services. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: remove all enabled flags from all tipc componentsYing Xue2014-02-221-5/+0
| | | | | | | | | | | | | | | | | | | | | | | When tipc module is inserted, many tipc components are initialized one by one. During the initialization period, if one of them is failed, tipc_core_stop() will be called to stop all components whatever corresponding components are created or not. To avoid to release uncreated ones, relevant components have to add necessary enabled flags indicating whether they are created or not. But in the initialization stage, if one component is unsuccessfully created, we will just destroy successfully created components before the failed component instead of all components. All enabled flags defined in components, in turn, become redundant. Additionally it's also unnecessary to identify whether table.types is NULL in tipc_nametbl_stop() because name stable has been definitely created successfully when tipc_nametbl_stop() is called. Cc: Jon Maloy <jon.maloy@ericsson.com> Cc: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: spelling fixesstephen hemminger2014-01-151-1/+1
| | | | | Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix oops when creating server socket failsYing Xue2013-08-021-3/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When creation of TIPC internal server socket fails, we get an oops with the following dump: BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 IP: [<ffffffffa0011f49>] tipc_close_conn+0x59/0xb0 [tipc] PGD 13719067 PUD 12008067 PMD 0 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: tipc(+) CPU: 4 PID: 4340 Comm: insmod Not tainted 3.10.0+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 task: ffff880014360000 ti: ffff88001374c000 task.ti: ffff88001374c000 RIP: 0010:[<ffffffffa0011f49>] [<ffffffffa0011f49>] tipc_close_conn+0x59/0xb0 [tipc] RSP: 0018:ffff88001374dc98 EFLAGS: 00010292 RAX: 0000000000000000 RBX: ffff880012ac09d8 RCX: 0000000000000000 RDX: 0000000000000046 RSI: 0000000000000001 RDI: ffff880014360000 RBP: ffff88001374dcb8 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0016fa0 R13: ffffffffa0017010 R14: ffffffffa0017010 R15: ffff880012ac09d8 FS: 0000000000000000(0000) GS:ffff880016600000(0063) knlGS:00000000f76668d0 CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b CR2: 0000000000000020 CR3: 0000000012227000 CR4: 00000000000006e0 Stack: ffff88001374dcb8 ffffffffa0016fa0 0000000000000000 0000000000000001 ffff88001374dcf8 ffffffffa0012922 ffff88001374dce8 00000000ffffffea ffffffffa0017100 0000000000000000 ffff8800134241a8 ffffffffa0017150 Call Trace: [<ffffffffa0012922>] tipc_server_stop+0xa2/0x1b0 [tipc] [<ffffffffa0009995>] tipc_subscr_stop+0x15/0x20 [tipc] [<ffffffffa00130f5>] tipc_core_stop+0x1d/0x33 [tipc] [<ffffffffa001f0d4>] tipc_init+0xd4/0xf8 [tipc] [<ffffffffa001f000>] ? 0xffffffffa001efff [<ffffffff8100023f>] do_one_initcall+0x3f/0x150 [<ffffffff81082f4d>] ? __blocking_notifier_call_chain+0x7d/0xd0 [<ffffffff810cc58a>] load_module+0x11aa/0x19c0 [<ffffffff810c8d60>] ? show_initstate+0x50/0x50 [<ffffffff8190311c>] ? retint_restore_args+0xe/0xe [<ffffffff810cce79>] SyS_init_module+0xd9/0x110 [<ffffffff8190dc65>] sysenter_dispatch+0x7/0x1f Code: 6c 24 70 4c 89 ef e8 b7 04 8f e1 8b 73 04 4c 89 e7 e8 7c 9e 32 e1 41 83 ac 24 b8 00 00 00 01 4c 89 ef e8 eb 0a 8f e1 48 8b 43 08 <4c> 8b 68 20 4d 8d a5 48 03 00 00 4c 89 e7 e8 04 05 8f e1 4c 89 RIP [<ffffffffa0011f49>] tipc_close_conn+0x59/0xb0 [tipc] RSP <ffff88001374dc98> CR2: 0000000000000020 ---[ end trace b02321f40e4269a3 ]--- We have the following call chain: tipc_core_start() ret = tipc_subscr_start() ret = tipc_server_start(){ server->enabled = 1; ret = tipc_open_listening_sock() } I.e., the server->enabled flag is unconditionally set to 1, whatever the return value of tipc_open_listening_sock(). This causes a crash when tipc_core_start() tries to clean up resources after a failed initialization: if (ret == failed) tipc_subscr_stop() tipc_server_stop(){ if (server->enabled) tipc_close_conn(){ NULL reference of con->sock-sk OOPS! } } To avoid this, tipc_server_start() should only set server->enabled to 1 in case of a succesful socket creation. In case of failure, it should release all allocated resources before returning. Problem introduced in commit c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f ("tipc: introduce new TIPC server infrastructure") in v3.11-rc1. Note that it won't be seen often; it takes a module load under memory constrained conditions in order to trigger the failure condition. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce new TIPC server infrastructureYing Xue2013-06-181-0/+596
TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>