perf annotate: Plug filename string leak

If dso__build_id_filename(..., NULL, ...) returns !NULL its because it
allocated it, so, when reaching the  'if (dso__is_kcore()) test, we
already checked that and were just "fallbacking" to using
dso->long_name, but without freeing filename, thus leaking it.

Fix it by adding the dso__is_kcore() test to the 'or' group just after
it, the one containing the full fallback code, including freeing the
filename.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: ee205503 ("perf tools: Fix annotation with kcore")
Link: http://lkml.kernel.org/n/tip-qi4rpjq8yo6myvg99kkgt0xz@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/annotate.c

@@ -1185,9 +1185,8 @@ int symbol__disassemble(struct symbol *sym, struct map *map, size_t privsize)
 		if (dso->has_build_id)
 			return ENOMEM;
 		goto fallback;
-	} else if (dso__is_kcore(dso)) {
-		goto fallback;
-	} else if (readlink(symfs_filename, command, sizeof(command)) < 0 ||
+	} else if (dso__is_kcore(dso) ||
+		   readlink(symfs_filename, command, sizeof(command)) < 0 ||
 		   strstr(command, DSO__NAME_KALLSYMS) ||
 		   access(symfs_filename, R_OK)) {
 		free(filename);