linux-toradex.git/net/tipc, branch v4.10

tipc: fix cleanup at module unload

2017-01-24T21:14:58+00:00

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 
Acked-by: Jon Maloy 
Tested-by: John Thompson 
Signed-off-by: Parthasarathy Bhuvaragan 
Signed-off-by: David S. Miller

tipc: ignore requests when the connection state is not CONNECTED

2017-01-24T21:14:58+00:00

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 
Acked-by: Jon Maloy 
Tested-by: John Thompson 
Signed-off-by: Parthasarathy Bhuvaragan 
Signed-off-by: David S. Miller

tipc: fix nametbl_lock soft lockup at module exit

2017-01-24T21:14:58+00:00

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 
Acked-by: Ying Xue 
Acked-by: Jon Maloy 
Signed-off-by: Parthasarathy Bhuvaragan 
Signed-off-by: David S. Miller

tipc: fix connection refcount error

2017-01-24T21:14:57+00:00

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 
Acked-by: Ying Xue 
Acked-by: Jon Maloy 
Signed-off-by: Parthasarathy Bhuvaragan 
Signed-off-by: David S. Miller

tipc: add subscription refcount to avoid invalid delete

2017-01-24T21:14:57+00:00

Until now, the subscribers keep track of the subscriptions using
reference count at subscriber level. At subscription cancel or
subscriber delete, we delete the subscription only if the timer
was pending for the subscription. This approach is incorrect as:
1. del_timer() is not SMP safe, if on CPU0 the check for pending
   timer returns true but CPU1 might schedule the timer callback
   thereby deleting the subscription. Thus when CPU0 is scheduled,
   it deletes an invalid subscription.
2. We export tipc_subscrp_report_overlap(), which accesses the
   subscription pointer multiple times. Meanwhile the subscription
   timer can expire thereby freeing the subscription and we might
   continue to access the subscription pointer leading to memory
   violations.

In this commit, we introduce subscription refcount to avoid deleting
an invalid subscription.

Reported-and-Tested-by: John Thompson 
Acked-by: Ying Xue 
Acked-by: Jon Maloy 
Signed-off-by: Parthasarathy Bhuvaragan 
Signed-off-by: David S. Miller

tipc: fix nametbl_lock soft lockup at node/link events

2017-01-24T21:14:57+00:00

We trigger a soft lockup as we grab nametbl_lock twice if the node
has a pending node up/down or link up/down event while:
- we process an incoming named message in tipc_named_rcv() and
  perform an tipc_update_nametbl().
- we have pending backlog items in the name distributor queue
  during a nametable update using tipc_nametbl_publish() or
  tipc_nametbl_withdraw().

The following are the call chain associated:
tipc_named_rcv() Grabs nametbl_lock
   tipc_update_nametbl() (publish/withdraw)
     tipc_node_subscribe()/unsubscribe()
       tipc_node_write_unlock()
          << lockup occurs if an outstanding node/link event
             exits, as we grabs nametbl_lock again >>

tipc_nametbl_withdraw() Grab nametbl_lock
  tipc_named_process_backlog()
    tipc_update_nametbl()
      << rest as above >>

The function tipc_node_write_unlock(), in addition to releasing the
lock processes the outstanding node/link up/down events. To do this,
we need to grab the nametbl_lock again leading to the lockup.

In this commit we fix the soft lockup by introducing a fast variant of
node_unlock(), where we just release the lock. We adapt the
node_subscribe()/node_unsubscribe() to use the fast variants.

Reported-and-Tested-by: John Thompson 
Acked-by: Ying Xue 
Acked-by: Jon Maloy 
Signed-off-by: Parthasarathy Bhuvaragan 
Signed-off-by: David S. Miller

tipc: allocate user memory with GFP_KERNEL flag

2017-01-16T18:31:53+00:00

Until now, we allocate memory always with GFP_ATOMIC flag.
When the system is under memory pressure and a user tries to send,
the send fails due to low memory. However, the user application
can wait for free memory if we allocate it using GFP_KERNEL flag.

In this commit, we use allocate memory with GFP_KERNEL for all user
allocation.

Reported-by: Rune Torgersen 
Acked-by: Jon Maloy 
Signed-off-by: Parthasarathy Bhuvaragan 
Signed-off-by: David S. Miller

tipc: don't send FIN message from connectionless socket

2016-12-23T22:53:47+00:00

In commit 6f00089c7372 ("tipc: remove SS_DISCONNECTING state") the
check for socket type is in the wrong place, causing a closing socket
to always send out a FIN message even when the socket was never
connected. This is normally harmless, since the destination node for
such messages most often is zero, and the message will be dropped, but
it is still a wrong and confusing behavior.

We fix this in this commit.

Reviewed-by: Parthasarathy Bhuvaragan 
Signed-off-by: Jon Maloy 
Signed-off-by: David S. Miller

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-12-16T18:24:44+00:00

Pull vfs updates from Al Viro:

 - more ->d_init() stuff (work.dcache)

 - pathname resolution cleanups (work.namei)

 - a few missing iov_iter primitives - copy_from_iter_full() and
   friends. Either copy the full requested amount, advance the iterator
   and return true, or fail, return false and do _not_ advance the
   iterator. Quite a few open-coded callers converted (and became more
   readable and harder to fuck up that way) (work.iov_iter)

 - several assorted patches, the big one being logfs removal

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  logfs: remove from tree
  vfs: fix put_compat_statfs64() does not handle errors
  namei: fold should_follow_link() with the step into not-followed link
  namei: pass both WALK_GET and WALK_MORE to should_follow_link()
  namei: invert WALK_PUT logics
  namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link()
  namei: saner calling conventions for mountpoint_last()
  namei.c: get rid of user_path_parent()
  switch getfrag callbacks to ..._full() primitives
  make skb_add_data,{_nocache}() and skb_copy_to_page_nocache() advance only on success
  [iov_iter] new primitives - copy_from_iter_full() and friends
  don't open-code file_inode()
  ceph: switch to use of ->d_init()
  ceph: unify dentry_operations instances
  lustre: switch to use of ->d_init()

[iov_iter] new primitives - copy_from_iter_full() and friends

2016-12-05T19:33:36+00:00

copy_from_iter_full(), copy_from_iter_full_nocache() and
csum_and_copy_from_iter_full() - counterparts of copy_from_iter()
et.al., advancing iterator only in case of successful full copy
and returning whether it had been successful or not.

Convert some obvious users.  *NOTE* - do not blindly assume that
something is a good candidate for those unless you are sure that
not advancing iov_iter in failure case is the right thing in
this case.  Anything that does short read/short write kind of
stuff (or is in a loop, etc.) is unlikely to be a good one.

Signed-off-by: Al Viro