linux-toradex.git/net/rds/tcp.c, branch v4.9.75

rds: tcp: Sequence teardown of listen and acceptor sockets to avoid races

2017-12-14T08:28:20+00:00

[ Upstream commit b21dd4506b71bdb9c5a20e759255cd2513ea7ebe ]

Commit a93d01f5777e ("RDS: TCP: avoid bad page reference in
rds_tcp_listen_data_ready") added the function
rds_tcp_listen_sock_def_readable()  to handle the case when a
partially set-up acceptor socket drops into rds_tcp_listen_data_ready().
However, if the listen socket (rtn->rds_tcp_listen_sock) is itself going
through a tear-down via rds_tcp_listen_stop(), the (*ready)() will be
null and we would hit a panic  of the form
  BUG: unable to handle kernel NULL pointer dereference at   (null)
  IP:           (null)
   :
  ? rds_tcp_listen_data_ready+0x59/0xb0 [rds_tcp]
  tcp_data_queue+0x39d/0x5b0
  tcp_rcv_established+0x2e5/0x660
  tcp_v4_do_rcv+0x122/0x220
  tcp_v4_rcv+0x8b7/0x980
    :
In the above case, it is not fatal to encounter a NULL value for
ready- we should just drop the packet and let the flush of the
acceptor thread finish gracefully.

In general, the tear-down sequence for listen() and accept() socket
that is ensured by this commit is:
     rtn->rds_tcp_listen_sock = NULL; /* prevent any new accepts */
     In rds_tcp_listen_stop():
         serialize with, and prevent, further callbacks using lock_sock()
         flush rds_wq
         flush acceptor workq
         sock_release(listen socket)

Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

RDS: TCP: unregister_netdevice_notifier() in error path of rds_tcp_init_net

2016-12-02T18:29:26+00:00

If some error is encountered in rds_tcp_init_net, make sure to
unregister_netdevice_notifier(), else we could trigger a panic
later on, when the modprobe from a netns fails.

Signed-off-by: Sowmini Varadhan 
Acked-by: Santosh Shilimkar 
Signed-off-by: David S. Miller

RDS: TCP: Enable multipath RDS for TCP

2016-07-15T18:36:58+00:00

Use RDS probe-ping to compute how many paths may be used with
the peer, and to synchronously start the multiple paths. If mprds is
supported, hash outgoing traffic to one of multiple paths in rds_sendmsg()
when multipath RDS is supported by the transport.

CC: Santosh Shilimkar 
Signed-off-by: Sowmini Varadhan 
Acked-by: Santosh Shilimkar 
Signed-off-by: David S. Miller

RDS: TCP: Reduce code duplication in rds_tcp_reset_callbacks()

2016-07-15T18:36:58+00:00

Some code duplication in rds_tcp_reset_callbacks() can be avoided
by having the function call rds_tcp_restore_callbacks() and
rds_tcp_set_callbacks().

Acked-by: Santosh Shilimkar 
Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: TCP: avoid bad page reference in rds_tcp_listen_data_ready

2016-07-15T18:36:57+00:00

As the existing comments in rds_tcp_listen_data_ready() indicate,
it is possible under some race-windows to get to this function with the
accept() socket. If that happens, we could run into a sequence whereby

   thread 1				thread 2

rds_tcp_accept_one() thread
sets up new_sock via ->accept().
The sk_user_data is now
sock_def_readable
					data comes in for new_sock,
					->sk_data_ready is called, and
					we land in rds_tcp_listen_data_ready
rds_tcp_set_callbacks()
takes the sk_callback_lock and
sets up sk_user_data to be the cp
					read_lock sk_callback_lock
					ready = cp
					unlock sk_callback_lock
					page fault on ready

In the above sequence, we end up with a panic on a bad page reference
when trying to execute (*ready)(). Instead we need to call
sock_def_readable() safely, which is what this patch achieves.

Acked-by: Santosh Shilimkar 
Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

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

2016-07-06T17:35:22+00:00

Conflicts:
	drivers/net/ethernet/mellanox/mlx5/core/en.h
	drivers/net/ethernet/mellanox/mlx5/core/en_main.c
	drivers/net/usb/r8152.c

All three conflicts were overlapping changes.

Signed-off-by: David S. Miller

RDS: fix rds_tcp_init() error path

2016-07-04T23:09:49+00:00

If register_pernet_subsys() fails, we shouldn't try to call
unregister_pernet_subsys().

Fixes: 467fa15356 ("RDS-TCP: Support multiple RDS-TCP listen endpoints, one per netns.")
Cc: stable@vger.kernel.org
Cc: Sowmini Varadhan 
Cc: David S. Miller 
Signed-off-by: Vegard Nossum 
Acked-by: Sowmini Varadhan 
Acked-by: Santosh Shilimkar 
Signed-off-by: David S. Miller

RDS: TCP: Hooks to set up a single connection path

2016-07-01T20:45:17+00:00

This patch adds ->conn_path_connect callbacks in the rds_transport
that are used to set up a single connection path.

Acked-by: Santosh Shilimkar 
Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: TCP: make receive path use the rds_conn_path

2016-07-01T20:45:17+00:00

The ->sk_user_data contains a pointer to the rds_conn_path
for the socket. Use this consistently in the rds_tcp_data_ready
callbacks to get the rds_conn_path for rds_recv_incoming.

Acked-by: Santosh Shilimkar 
Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: TCP: make ->sk_user_data point to a rds_conn_path

2016-07-01T20:45:17+00:00

The socket callbacks should all operate on a struct rds_conn_path,
in preparation for a MP capable RDS-TCP.

Acked-by: Santosh Shilimkar 
Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller