svn commit: r343521 - stable/12/sys/dev/netmap

[Vincenzo Maffione]

Author: vmaffione
Date: Mon Jan 28 09:18:28 2019
New Revision: 343521
URL: https://svnweb.freebsd.org/changeset/base/343521

Log:
  MFC r343413
  
  netmap: fix crash with monitors and VALE ports
  
  Crash report described here:
      https://github.com/luigirizzo/netmap/issues/583
  Fixed by providing dummy sync callback in case it is missing.

Modified:
  stable/12/sys/dev/netmap/netmap_monitor.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/dev/netmap/netmap_monitor.c
==============================================================================
--- stable/12/sys/dev/netmap/netmap_monitor.c	Mon Jan 28 08:36:10 2019	(r343520)
+++ stable/12/sys/dev/netmap/netmap_monitor.c	Mon Jan 28 09:18:28 2019	(r343521)
@@ -259,11 +259,20 @@ static int netmap_monitor_parent_txsync(struct netmap_
 static int netmap_monitor_parent_rxsync(struct netmap_kring *, int);
 static int netmap_monitor_parent_notify(struct netmap_kring *, int);
 
+static int
+nm_monitor_dummycb(struct netmap_kring *kring, int flags)
+{
+	(void)kring;
+	(void)flags;
+	return 0;
+}
+
 static void
 nm_monitor_intercept_callbacks(struct netmap_kring *kring)
 {
 	ND("intercept callbacks on %s", kring->name);
-	kring->mon_sync = kring->nm_sync;
+	kring->mon_sync = kring->nm_sync != NULL ?
+		kring->nm_sync : nm_monitor_dummycb;
 	kring->mon_notify = kring->nm_notify;
 	if (kring->tx == NR_TX) {
 		kring->nm_sync = netmap_monitor_parent_txsync;