svn commit: r304579 - head/sys/netinet

[Michael Tuexen]

Author: tuexen
Date: Mon Aug 22 01:45:29 2016
New Revision: 304579
URL: https://svnweb.freebsd.org/changeset/base/304579

Log:
  Improve the locking when sending user messages.
  
  First, keep a ref count on the stcb after looking it up, as
  done in the other lookup cases.
  Second, before looking again at sp, ensure that it is not
  freed, because the assoc is about to be freed.
  
  MFC after: 3 days

Modified:
  head/sys/netinet/sctp_output.c

Modified: head/sys/netinet/sctp_output.c
==============================================================================
--- head/sys/netinet/sctp_output.c	Mon Aug 22 01:43:47 2016	(r304578)
+++ head/sys/netinet/sctp_output.c	Mon Aug 22 01:45:29 2016	(r304579)
@@ -12639,7 +12639,10 @@ sctp_lower_sosend(struct socket *so,
 		}
 		SCTP_INP_RUNLOCK(inp);
 	} else if (sinfo_assoc_id) {
-		stcb = sctp_findassociation_ep_asocid(inp, sinfo_assoc_id, 0);
+		stcb = sctp_findassociation_ep_asocid(inp, sinfo_assoc_id, 1);
+		if (stcb != NULL) {
+			hold_tcblock = 1;
+		}
 	} else if (addr) {
 		/*-
 		 * Since we did not use findep we must
@@ -13404,6 +13407,10 @@ skip_preblock:
 			}
 		}
 		SCTP_TCB_SEND_LOCK(stcb);
+		if (stcb->asoc.state & SCTP_STATE_ABOUT_TO_BE_FREED) {
+			SCTP_TCB_SEND_UNLOCK(stcb);
+			goto out_unlocked;
+		}
 		if (sp) {
 			if (sp->msg_is_complete == 0) {
 				strm->last_msg_incomplete = 1;