linux/net/tipc/socket.c, branch v3.13

tipc: fix deadlock during socket release

2013-12-30T03:24:07Z

A deadlock might occur if name table is withdrawn in socket release routine, and while packets are still being received from bearer. CPU0 CPU1 T0: recv_msg() release() T1: tipc_recv_msg() tipc_withdraw() T2: [grab node lock] [grab port lock] T3: tipc_link_wakeup_ports() tipc_nametbl_withdraw() T4: [grab port lock]* named_cluster_distribute() T5: wakeupdispatch() tipc_link_send() T6: [grab node lock]* The opposite order of holding port lock and node lock on above two different paths may result in a deadlock. If socket lock instead of port lock is used to protect port instance in tipc_withdraw(), the reverse order of holding port lock and node lock will be eliminated, as a result, the deadlock is killed as well. Reported-by: Lars Everbrand Reviewed-by: Erik Hugne Signed-off-by: Ying Xue Signed-off-by: David S. Miller

net: rework recvmsg handler msg_name and msg_namelen logic

2013-11-21T02:52:30Z

This patch now always passes msg->msg_namelen as 0. recvmsg handlers must set msg_namelen to the proper size <= sizeof(struct sockaddr_storage) to return msg_name to the user. This prevents numerous uninitialized memory leaks we had in the recvmsg handlers and makes it harder for new code to accidentally leak uninitialized memory. Optimize for the case recvfrom is called with NULL as address. We don't need to copy the address at all, so set it to NULL before invoking the recvmsg handler. We can do so, because all the recvmsg handlers must cope with the case a plain read() is called on them. read() also sets msg_name to NULL. Also document these changes in include/linux/net.h as suggested by David Miller. Changes since RFC: Set msg->msg_name = NULL if user specified a NULL in msg_name but had a non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't affect sendto as it would bail out earlier while trying to copy-in the address. It also more naturally reflects the logic by the callers of verify_iovec. With this change in place I could remove " if (!uaddr || msg_sys->msg_namelen == 0) msg->msg_name = NULL ". This change does not alter the user visible error logic as we ignore msg_namelen as long as msg_name is NULL. Also remove two unnecessary curly brackets in ___sys_recvmsg and change comments to netdev style. Cc: David Miller Suggested-by: Eric Dumazet Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller

tipc: silence sparse warnings

2013-10-18T17:20:42Z

Eliminate below sparse warnings: net/tipc/link.c:1210:37: warning: cast removes address space of expression net/tipc/link.c:1218:59: warning: incorrect type in argument 2 (different address spaces) net/tipc/link.c:1218:59: expected void const [noderef] *from net/tipc/link.c:1218:59: got unsigned char const [usertype] *[assigned] sect_crs net/tipc/socket.c:341:49: warning: Using plain integer as NULL pointer net/tipc/socket.c:1371:36: warning: Using plain integer as NULL pointer net/tipc/socket.c:1694:57: warning: Using plain integer as NULL pointer Signed-off-by: Ying Xue Signed-off-by: Andreas Bofjäll Reviewed-by: Paul Gortmaker Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: remove iovec length parameter from all sending functions

2013-10-18T17:20:42Z

tipc_msg_build() now copies message data from iovec to skb_buff using memcpy_fromiovecend(), which doesn't need to be passed the iovec length to perform the copying. So we remove the parameter indicating iovec length in all functions where TIPC messages are built and sent. Signed-off-by: Ying Xue Reviewed-by: Paul Gortmaker Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: set sk_err correctly when connection fails

2013-08-30T20:06:57Z

Should a connect fail, if the publication/server is unavailable or due to some other error, a positive value will be returned and errno is never set. If the application code checks for an explicit zero return from connect (success) or a negative return (failure), it will not catch the error and subsequent send() calls will fail as shown from the strace snippet below. socket(0x1e /* PF_??? */, SOCK_SEQPACKET, 0) = 3 connect(3, {sa_family=0x1e /* AF_??? */, sa_data="\2\1\322\4\0\0\322\4\0\0\0\0\0\0"}, 16) = 111 sendto(3, "test", 4, 0, NULL, 0) = -1 EPIPE (Broken pipe) The reason for this behaviour is that TIPC wrongly inverts error codes set in sk_err. Signed-off-by: Erik Hugne Signed-off-by: David S. Miller

tipc: cosmetic realignment of function arguments

2013-06-17T22:53:01Z

No runtime code changes here. Just a realign of the function arguments to start where the 1st one was, and fit as many args as can be put in an 80 char line. Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller

tipc: save sock structure pointer instead of void pointer to tipc_port

2013-06-17T22:53:01Z

Directly save sock structure pointer instead of void pointer to avoid unnecessary cast conversions. Signed-off-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller

tipc: rename tipc_createport_raw to tipc_createport

2013-06-17T22:53:01Z

After the removal of the native API, there is now only one way to to create a TIPC port instance -- the function tipc_createport_raw(). We make it more readable by renaming it to tipc_createport(). Signed-off-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller

tipc: convert configuration server to use new server facility

2013-06-17T22:53:00Z

As the new socket-based TIPC server infrastructure has been introduced, we can now convert the configuration server to use it. Then we can take future steps to simplify the configuration server locking policy. Some minor reordering of initialization is done, due to the dependency on having tipc_socket_init completed. Signed-off-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller

tipc: convert topology server to use new server facility

2013-06-17T22:53:00Z

As the new TIPC server infrastructure has been introduced, we can now convert the TIPC topology server to it. We get two benefits from doing this: 1) It simplifies the topology server locking policy. In the original locking policy, we placed one spin lock pointer in the tipc_subscriber structure to reuse the lock of the subscriber's server port, controlling access to members of tipc_subscriber instance. That is, we only used one lock to ensure both tipc_port and tipc_subscriber members were safely accessed. Now we introduce another spin lock for tipc_subscriber structure only protecting themselves, to get a finer granularity locking policy. Moreover, the change will allow us to make the topology server code more readable and maintainable. 2) It fixes a bug where sent subscription events may be lost when the topology port is congested. Using the new service, the topology server now queues sent events into an outgoing buffer, and then wakes up a sender process which has been blocked in workqueue context. The process will keep picking events from the buffer and send them to their respective subscribers, using the kernel socket interface, until the buffer is empty. Even if the socket is congested during transmission there is no risk that events may be dropped, since the sender process may block when needed. Some minor reordering of initialization is done, since we now have a scenario where the topology server must be started after socket initialization has taken place, as the former depends on the latter. And overall, we see a simplification of the TIPC subscriber code in making this changeover. Signed-off-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: Paul Gortmaker Signed-off-by: David S. Miller