re: net: sctp: rework multihoming retransmission path selection to rfc4960

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Daniel Borkmann,

This is a semi-automatic email about new static checker warnings.

The patch 4c47af4d5eb2: "net: sctp: rework multihoming retransmission
path selection to rfc4960" from Feb 20, 2014, leads to the following
Smatch complaint:

net/sctp/associola.c:1322 sctp_assoc_update_retran_path()
	 warn: variable dereferenced before check 'trans_next' (see line 1319)

net/sctp/associola.c
  1305          /* Iterate from retran_path's successor back to retran_path. */
  1306          for (trans = list_next_entry(trans, transports); 1;
  1307               trans = list_next_entry(trans, transports)) {
  1308                  /* Manually skip the head element. */
  1309                  if (&trans->transports = &asoc->peer.transport_addr_list)
  1310                          continue;
  1311                  if (trans->state = SCTP_UNCONFIRMED)
  1312                          continue;
  1313                  trans_next = sctp_trans_elect_best(trans, trans_next);
  1314                  /* Active is good enough for immediate return. */
  1315                  if (trans_next->state = SCTP_ACTIVE)
                            ^^^^^^^^^^^^^^^^^
Dereference.

  1316                          break;
                                ^^^^^^
  1317                  /* We've reached the end, time to update path. */
  1318			if (trans = asoc->peer.retran_path)
  1319				break;
                                ^^^^^
These two breaks are the the only way to exit from the loop.

  1320		}
  1321	
  1322		if (trans_next != NULL)
                    ^^^^^^^^^^^^^^^^^^
Check to late.

  1323			asoc->peer.retran_path = trans_next;
  1324	

regards,
dan carpenter