Silence cppcheck 2.2 false positive in udp_recv()

cppcheck 2.2 reports the following false positive:

    lib/dns/dispatch.c:1220:14: warning: Either the condition 'resp==NULL' is redundant or there is possible null pointer dereference: resp. [nullPointerRedundantCheck]
     if (disp != resp->disp) {
                 ^
    lib/dns/dispatch.c:1191:11: note: Assuming that condition 'resp==NULL' is not redundant
     if (resp == NULL) {
              ^
    lib/dns/dispatch.c:1220:14: note: Null pointer dereference
     if (disp != resp->disp) {
                 ^

Apparently this version of cppcheck gets confused about conditional
"goto" statements because line 1220 can never be reached if 'resp' is
NULL.

Move a code block to prevent the above false positive from being
reported without affecting the processing logic.

(cherry picked from commit 0b6216d1c702ef0aaa66a2a1bea70cfb12c81468)

diff --git a/lib/dns/dispatch.c b/lib/dns/dispatch.c
index 80d76b79c95a097f904460943f66e6d0bd0cdb7d..0252803a29b4395443d87990857cedc1b5dfa428 100644 (file)
--- a/lib/dns/dispatch.c
+++ b/lib/dns/dispatch.c
@@ -1198,11 +1198,6 @@ udp_recv(isc_event_t *ev_in, dns_dispatch_t *disp, dispsocket_t *dispsock) {
                             "search for response in bucket %d: %s",
                             bucket, (resp == NULL ? "not found" : "found"));
 
-               if (resp == NULL) {
-                       inc_stats(mgr, dns_resstatscounter_mismatch);
-                       free_buffer(disp, ev->region.base, ev->region.length);
-                       goto unlock;
-               }
        } else if (resp->id != id || !isc_sockaddr_equal(&ev->address,
                                                         &resp->host)) {
                dispatch_log(disp, LVL(90),
@@ -1212,6 +1207,12 @@ udp_recv(isc_event_t *ev_in, dns_dispatch_t *disp, dispsocket_t *dispsock) {
                goto unlock;
        }
 
+       if (resp == NULL) {
+               inc_stats(mgr, dns_resstatscounter_mismatch);
+               free_buffer(disp, ev->region.base, ev->region.length);
+               goto unlock;
+       }
+
        /*
         * Now that we have the original dispatch the query was sent
         * from check that the address and port the response was