[ovs-discuss] Incorrect Spanning tree status

[Ben Pfaff]

On Mon, Feb 17, 2014 at 06:58:58PM -0500, Vasu Dasari wrote:
> On debugging this issue further, I found that, ofproto's STP state bits are
> getting updated correctly because of following call stack:
> 
> #0  ofproto_port_set_state (port=0x82395c0, state=OFPUTIL_PS_STP_FORWARD)
>     at ../ofproto/ofproto.c:2267
> #1  0x0806d659 in update_stp_port_state (ofport=0x82395b8)
>     at ../ofproto/ofproto-dpif.c:1866
> #2  0x0806da37 in stp_run (ofproto=0x822c628) at
> ../ofproto/ofproto-dpif.c:1969
> #3  0x0806c1ba in run (ofproto_=0x822c630) at ../ofproto/ofproto-dpif.c:1286
> #4  0x0805d51f in ofproto_run (p=0x822c630) at ../ofproto/ofproto.c:1429
> #5  0x08050ece in bridge_run__ () at ../vswitchd/bridge.c:2275
> #6  0x08051032 in bridge_run () at ../vswitchd/bridge.c:2326
> #7  0x08055a99 in main (argc=4, argv=0xbffff224) at
> ../vswitchd/ovs-vswitchd.c:118
> 
> but the same STP state is getting overwritten by following call stack, at a
> later point in time:
> 
> #0  ofport_modified (port=0x822c290, pp=0xbfffefb4) at
> ../ofproto/ofproto.c:2244
> #1  0x0805f887 in update_port (ofproto=0x821f090, name=0x8200958
> "atl0-eth2")
>     at ../ofproto/ofproto.c:2423
> #2  0x0805d867 in ofproto_run (p=0x821f090) at ../ofproto/ofproto.c:1495
> #3  0x08050ece in bridge_run__ () at ../vswitchd/bridge.c:2275
> #4  0x08051032 in bridge_run () at ../vswitchd/bridge.c:2326
> #5  0x08055a99 in main (argc=4, argv=0xbffff224) at
> ../vswitchd/ovs-vswitchd.c:118
> 
> This is the reason why, I am seeing the "state to be 0".

It looks very much to me like ofport_modified() simply shouldn't be
messing around with any of the state bits other than
OFPUTIL_PS_LINK_DOWN.  Can you try this patch?  If it solves the
problem I'll write it up properly.

diff --git a/ofproto/ofproto.c b/ofproto/ofproto.c
index 48e10ca..f544c68 100644
--- a/ofproto/ofproto.c
+++ b/ofproto/ofproto.c
@@ -2244,7 +2244,8 @@ ofport_modified(struct ofport *port, struct ofputil_phy_port *pp)
     memcpy(port->pp.hw_addr, pp->hw_addr, ETH_ADDR_LEN);
     port->pp.config = ((port->pp.config & ~OFPUTIL_PC_PORT_DOWN)
                         | (pp->config & OFPUTIL_PC_PORT_DOWN));
-    port->pp.state = pp->state;
+    port->pp.state = ((port->ps.state & ~OFPUTIL_PS_LINK_DOWN)
+                      | (pp->state & OFPUTIL_PS_LINK_DOWN));
     port->pp.curr = pp->curr;
     port->pp.advertised = pp->advertised;
     port->pp.supported = pp->supported;