svn commit: r303836 - head/sys/dev/bxe

[Ryan Stone]

Author: rstone
Date: Mon Aug  8 16:19:24 2016
New Revision: 303836
URL: https://svnweb.freebsd.org/changeset/base/303836

Log:
  Don't enqueue NULL on a drbr
  
  In one corner case in the bxe TX path, a NULL mbuf could be enqueued onto
  a drbr queue.  This could case a KASSERT to fire with INVARIANTS enabled,
  or the processing of packets from the queue to be prematurely ended later
  on.
  
  Submitted by:	Matt Joras (matt.joras AT isilon.com)
  Reviewed by:	davidcs
  MFC after:	3 days
  Sponsored by:	EMC / Isilon Storage Division
  Differential Revision:	https://reviews.freebsd.org/D7041

Modified:
  head/sys/dev/bxe/bxe.c

Modified: head/sys/dev/bxe/bxe.c
==============================================================================
--- head/sys/dev/bxe/bxe.c	Mon Aug  8 15:07:38 2016	(r303835)
+++ head/sys/dev/bxe/bxe.c	Mon Aug  8 16:19:24 2016	(r303836)
@@ -5624,7 +5624,8 @@ bxe_tx_mq_start_locked(struct bxe_softc 
     if (!sc->link_vars.link_up ||
         (if_getdrvflags(ifp) &
         (IFF_DRV_RUNNING | IFF_DRV_OACTIVE)) != IFF_DRV_RUNNING) {
-        rc = drbr_enqueue(ifp, tx_br, m);
+        if (m != NULL)
+            rc = drbr_enqueue(ifp, tx_br, m);
         goto bxe_tx_mq_start_locked_exit;
     }