net/colo: Match is-enabled probe to tracepoint

Build of QEMU with dtrace fails on macOS:

  LINK    x86_64-softmmu/qemu-system-x86_64
error: probe colo_compare_miscompare doesn't exist
error: Could not register probes
ld: error creating dtrace DOF section for architecture x86_64

The reason of the error is explained by Adam Leventhal [1]:

  Note that is-enabled probes don't have the stability magic so I'm not
  sure how things would work if only is-enabled probes were used.

net/colo code uses is-enabled probes to determine if other probes should
be used but colo_compare_miscompare itself is not used explicitly.
Linker doesn't include the symbol and build fails.

The issue can be resolved if is-enabled probe matches the actual trace
point that is used inside the test. Packet dump toggle is replaced with
a compile-time conditional definition.

1. http://markmail.org/message/6grq2ygr5nwdwsnb

Fixes: f4b618360e ("colo-compare: add TCP, UDP, ICMP packet comparison")
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Cameron Esfahani <dirty@apple.com>
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Message-id: 20200717093517.73397-5-r.bolshakov@yadro.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 22 insertions, 20 deletions

diff --git a/net/colo-compare.c b/net/colo-compare.c
index 2c20de1537..0b3215dee0 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -54,6 +54,8 @@ static NotifierList colo_compare_notifiers =
 #define REGULAR_PACKET_CHECK_MS 3000
 #define DEFAULT_TIME_OUT_MS 3000
 
+/* #define DEBUG_COLO_PACKETS */
+
 static QemuMutex colo_compare_mutex;
 static bool colo_compare_active;
 static QemuMutex event_mtx;
@@ -328,7 +330,7 @@ static int colo_compare_packet_payload(Packet *ppkt,
                                        uint16_t len)
 
 {
-    if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
+    if (trace_event_get_state_backends(TRACE_COLO_COMPARE_IP_INFO)) {
         char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
 
         strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
@@ -493,12 +495,12 @@ sec:
         g_queue_push_head(&conn->primary_list, ppkt);
         g_queue_push_head(&conn->secondary_list, spkt);
 
-        if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
-            qemu_hexdump((char *)ppkt->data, stderr,
-                        "colo-compare ppkt", ppkt->size);
-            qemu_hexdump((char *)spkt->data, stderr,
-                        "colo-compare spkt", spkt->size);
-        }
+#ifdef DEBUG_COLO_PACKETS
+        qemu_hexdump((char *)ppkt->data, stderr,
+                     "colo-compare ppkt", ppkt->size);
+        qemu_hexdump((char *)spkt->data, stderr,
+                     "colo-compare spkt", spkt->size);
+#endif
 
         colo_compare_inconsistency_notify(s);
     }
@@ -534,12 +536,12 @@ static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
                                     ppkt->size - offset)) {
         trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size);
         trace_colo_compare_udp_miscompare("Secondary pkt size", spkt->size);
-        if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
-            qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
-                         ppkt->size);
-            qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
-                         spkt->size);
-        }
+#ifdef DEBUG_COLO_PACKETS
+        qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
+                     ppkt->size);
+        qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
+                     spkt->size);
+#endif
         return -1;
     } else {
         return 0;
@@ -577,12 +579,12 @@ static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
                                            ppkt->size);
         trace_colo_compare_icmp_miscompare("Secondary pkt size",
                                            spkt->size);
-        if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
-            qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
-                         ppkt->size);
-            qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
-                         spkt->size);
-        }
+#ifdef DEBUG_COLO_PACKETS
+        qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt",
+                     ppkt->size);
+        qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt",
+                     spkt->size);
+#endif
         return -1;
     } else {
         return 0;
@@ -598,7 +600,7 @@ static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
     uint16_t offset = ppkt->vnet_hdr_len;
 
     trace_colo_compare_main("compare other");
-    if (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) {
+    if (trace_event_get_state_backends(TRACE_COLO_COMPARE_IP_INFO)) {
         char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
 
         strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));