ofproto-dpif: Zero-out subfacet counters when installation fails.

When deleting subfacets, subfacet_uninstall() asserts that the
subfacet's counters are zero to make sure we don't lose counters.  We
have seen cases where a subfacet cannot be installed, but the counters
have values.  This should not happen and indicates a bug, since we
shouldn't create a subfacet if the datapath has a flow.  A buggy
datapath could trigger this, so just zero out the counters and log an
error.

Bug #18460.

Signed-off-by: Justin Pettit <jpettit@nicira.com>

diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index c1a85b6..78109b9 100644 (file)
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -4160,6 +4160,18 @@ handle_miss_upcalls(struct dpif_backer *backer, struct dpif_upcall *upcalls,
 
             COVERAGE_INC(subfacet_install_fail);
 
+            /* Zero-out subfacet counters when installation failed, but
+             * datapath reported hits.  This should not happen and
+             * indicates a bug, since if the datapath flow exists, we
+             * should not be attempting to create a new subfacet.  A
+             * buggy datapath could trigger this, so just zero out the
+             * counters and log an error. */
+            if (subfacet->dp_packet_count || subfacet->dp_byte_count) {
+                VLOG_ERR_RL(&rl, "failed to install subfacet for which "
+                            "datapath reported hits");
+                subfacet->dp_packet_count = subfacet->dp_byte_count = 0;
+            }
+
             subfacet->path = SF_NOT_INSTALLED;
         }