svn commit: r230024 - head/sys/dev/e1000

[Luigi Rizzo]

Author: luigi
Date: Thu Jan 12 17:30:44 2012
New Revision: 230024
URL: http://svn.freebsd.org/changeset/base/230024

Log:
  clear the pointer after freeing the mbuf. Without that, we
  risk a double free if the subsequent mbuf allocation fails.
  This bug is not netmap-related and was introduced in  rev. 228387

Modified:
  head/sys/dev/e1000/if_em.c

Modified: head/sys/dev/e1000/if_em.c
==============================================================================
--- head/sys/dev/e1000/if_em.c	Thu Jan 12 17:28:00 2012	(r230023)
+++ head/sys/dev/e1000/if_em.c	Thu Jan 12 17:30:44 2012	(r230024)
@@ -4044,6 +4044,7 @@ em_setup_receive_ring(struct rx_ring *rx
 			    BUS_DMASYNC_POSTREAD);
 			bus_dmamap_unload(rxr->rxtag, rxbuf->map);
 			m_freem(rxbuf->m_head);
+			rxbuf->m_head = NULL; /* mark as freed */
 		}
 	}