[ovs-dev] [PATCH] netdev, dpif: fix the crash/assert on port delete

Ashish Varma ashishvarma.ovs at gmail.com
Fri Nov 3 14:36:41 UTC 2017


a crash is seen in "netdev_ports_remove" when an interface is deleted and added
back in the system and when the interface is part of a bridge configuration.
e.g. steps:
  create a tap0 interface using "ip tuntap add.."
  add the tap0 interface to br0 using "ovs-vsctl add-port.."
  delete the tap0 interface from system using "ip tuntap del.."
  add the tap0 interface back in system using "ip tuntap add.."
                       (this changes the ifindex of the interface)
  delete tap0 from br0 using "ovs-vsctl del-port.."

In the function "netdev_ports_insert", two hmap entries were created for
mapping "portnum -> netdev" and "ifindex -> portnum".
When the interface is deleted from the system, the "netdev_ports_remove"
function is not getting called and the old ifindex entry is not getting
cleaned up from the "ifindex_to_port" hmap.

As part of the fix, added function "dpif_port_remove" which will call
"netdev_ports_remove" in the path where the interface deletion from the system
is detected.
Also, in "netdev_ports_remove", added the code where the "ifindex_to_port_data"
(ifindex -> portnum map node) is getting freed when the ifindex is not
available any more. (as the interface is already deleted.)

VMware-BZ: #1975788
Signed-off-by: Ashish Varma <ashishvarma.ovs at gmail.com>
---
 AUTHORS.rst            |  1 +
 lib/dpif.c             |  6 ++++++
 lib/dpif.h             |  1 +
 lib/netdev.c           | 22 +++++++++++++++-------
 ofproto/ofproto-dpif.c |  6 ++++++
 5 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/AUTHORS.rst b/AUTHORS.rst
index 3d61c04..7eecd54 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -62,6 +62,7 @@ Ariel Tubaltsev                 atubaltsev at vmware.com
 Arnoldo Lutz                    arnoldo.lutz.guevara at hpe.com
 Arun Sharma                     arun.sharma at calsoftinc.com
 Aryan TaheriMonfared            aryan.taherimonfared at uis.no
+Ashish Varma                    ashishvarma.ovs at gmail.com
 Ashwin Swaminathan              ashwinds at arista.com
 Babu Shanmugam                  bschanmu at redhat.com
 Ben Pfaff                       blp at ovn.org
diff --git a/lib/dpif.c b/lib/dpif.c
index 3233bc8..6b2734b 100644
--- a/lib/dpif.c
+++ b/lib/dpif.c
@@ -623,6 +623,12 @@ dpif_port_del(struct dpif *dpif, odp_port_t port_no)
     return error;
 }
 
+int
+dpif_port_remove(struct dpif *dpif, odp_port_t port_no)
+{
+    return netdev_ports_remove(port_no, dpif->dpif_class);
+}
+
 /* Makes a deep copy of 'src' into 'dst'. */
 void
 dpif_port_clone(struct dpif_port *dst, const struct dpif_port *src)
diff --git a/lib/dpif.h b/lib/dpif.h
index d9ded8b..c2d1c61 100644
--- a/lib/dpif.h
+++ b/lib/dpif.h
@@ -452,6 +452,7 @@ const char *dpif_port_open_type(const char *datapath_type,
                                 const char *port_type);
 int dpif_port_add(struct dpif *, struct netdev *, odp_port_t *port_nop);
 int dpif_port_del(struct dpif *, odp_port_t port_no);
+int dpif_port_remove(struct dpif *, odp_port_t port_no);
 
 /* A port within a datapath.
  *
diff --git a/lib/netdev.c b/lib/netdev.c
index 704b38f..954da92 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -2179,6 +2179,7 @@ struct ifindex_to_port_data {
     struct hmap_node node;
     int ifindex;
     odp_port_t port;
+    const struct dpif_class *dpif_class;
 };
 
 #define NETDEV_PORTS_HASH_INT(port, dpif) \
@@ -2228,6 +2229,7 @@ netdev_ports_insert(struct netdev *netdev, const struct dpif_class *dpif_class,
     ifidx = xzalloc(sizeof *ifidx);
     ifidx->ifindex = ifindex;
     ifidx->port = dpif_port->port_no;
+    ifidx->dpif_class = dpif_class;
 
     hmap_insert(&port_to_netdev, &data->node, hash);
     hmap_insert(&ifindex_to_port, &ifidx->node, ifidx->ifindex);
@@ -2266,10 +2268,9 @@ netdev_ports_remove(odp_port_t port_no, const struct dpif_class *dpif_class)
 
     if (data) {
         int ifindex = netdev_get_ifindex(data->netdev);
+        struct ifindex_to_port_data *ifidx = NULL;
 
         if (ifindex > 0) {
-            struct ifindex_to_port_data *ifidx = NULL;
-
             HMAP_FOR_EACH_WITH_HASH (ifidx, node, ifindex, &ifindex_to_port) {
                 if (ifidx->port == port_no) {
                     hmap_remove(&ifindex_to_port, &ifidx->node);
@@ -2279,11 +2280,18 @@ netdev_ports_remove(odp_port_t port_no, const struct dpif_class *dpif_class)
             }
             ovs_assert(ifidx);
         } else {
-            static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
-
-            VLOG_WARN_RL(&rl, "netdev ports map has dpif port %"PRIu32
-                         " but netdev has no ifindex: %s", port_no,
-                         ovs_strerror(ifindex));
+            /* case where the interface is already deleted form the datapath
+             * (e.g. tunctl -d or ip tuntap del), then the ifindex is not
+             * valid anymore. Traverse the HMAP for the port number. */
+            HMAP_FOR_EACH (ifidx, node, &ifindex_to_port) {
+                if ((ifidx->port == port_no) &&
+                    (ifidx->dpif_class == dpif_class)) {
+                    hmap_remove(&ifindex_to_port, &ifidx->node);
+                    free(ifidx);
+                    break;
+                }
+            }
+            ovs_assert(ifidx);
         }
 
         dpif_port_destroy(&data->dpif_port);
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 4bc942d..779aef6 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -1923,6 +1923,12 @@ port_destruct(struct ofport *port_, bool del)
         if (!port->is_tunnel) {
             dpif_port_del(ofproto->backer->dpif, port->odp_port);
         }
+    } else if (del) {
+        /* The underlying device is already deleted (e.g. tunctl -d).
+         * Calling dpif_port_remove to do local cleanup for the netdev */
+        if (!port->is_tunnel) {
+            dpif_port_remove(ofproto->backer->dpif, port->odp_port);
+        }
     }
 
     if (port->peer) {
-- 
2.7.4



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