update_port() can delete the port for which it is called, if the underlying
network device has been destroyed, so HMAP_FOR_EACH is unsafe in
ofproto_run().
Less obviously, update_port() can delete unrelated ports. For example,
suppose that initially device A is port 1 and device B is port 2. If
update_port("A") runs just after this, then it will ofport_remove() both
ports, then ofport_install() A as the new port 2.
So this commit first assembles a list of ports to update, then updates them
in a separate loop.
Without this commit, running "ovs-dpctl del-dp" while ovs-vswitchd is
running consistently causes a crash for me within a few seconds.
Signed-off-by: Ben Pfaff <[email protected]>
---
ofproto/ofproto.c | 18 ++++++++++++++++--
1 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/ofproto/ofproto.c b/ofproto/ofproto.c
index f934306..cb46d26 100644
--- a/ofproto/ofproto.c
+++ b/ofproto/ofproto.c
@@ -1027,8 +1027,9 @@ process_port_change(struct ofproto *ofproto, int error,
char *devname)
int
ofproto_run(struct ofproto *p)
{
+ struct sset changed_netdevs;
+ const char *changed_netdev;
struct ofport *ofport;
- char *devname;
int error;
error = p->ofproto_class->run(p);
@@ -1037,18 +1038,31 @@ ofproto_run(struct ofproto *p)
}
if (p->ofproto_class->port_poll) {
+ char *devname;
+
while ((error = p->ofproto_class->port_poll(p, &devname)) != EAGAIN) {
process_port_change(p, error, devname);
}
}
+ /* Update OpenFlow port status for any port whose netdev has changed.
+ *
+ * Refreshing a given 'ofport' can cause an arbitrary ofport to be
+ * destroyed, so it's not safe to update ports directly from the
+ * HMAP_FOR_EACH loop, or even to use HMAP_FOR_EACH_SAFE. Instead, we
+ * need this two-phase approach. */
+ sset_init(&changed_netdevs);
HMAP_FOR_EACH (ofport, hmap_node, &p->ports) {
unsigned int change_seq = netdev_change_seq(ofport->netdev);
if (ofport->change_seq != change_seq) {
ofport->change_seq = change_seq;
- update_port(p, netdev_get_name(ofport->netdev));
+ sset_add(&changed_netdevs, netdev_get_name(ofport->netdev));
}
}
+ SSET_FOR_EACH (changed_netdev, &changed_netdevs) {
+ update_port(p, changed_netdev);
+ }
+ sset_destroy(&changed_netdevs);
switch (p->state) {
case S_OPENFLOW:
--
1.7.2.5
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