[PATCH bpf-next 1/3] selftests/bpf: fix bogus uninitialized variable warning

[Andrii Nakryiko <andrii@kernel.org>]

When compiling selftests/bpf in optimized mode (-O2), GCC erroneously
complains about uninitialized token variable:

  In file included from network_helpers.c:22:
  network_helpers.c: In function ‘open_netns’:
  test_progs.h:355:22: error: ‘token’ may be used uninitialized [-Werror=maybe-uninitialized]
    355 |         int ___err = libbpf_get_error(___res);                          \
        |                      ^~~~~~~~~~~~~~~~~~~~~~~~
  network_helpers.c:440:14: note: in expansion of macro ‘ASSERT_OK_PTR’
    440 |         if (!ASSERT_OK_PTR(token, "malloc token"))
        |              ^~~~~~~~~~~~~
  In file included from /data/users/andriin/linux/tools/testing/selftests/bpf/tools/include/bpf/libbpf.h:21,
                   from bpf_util.h:9,
                   from network_helpers.c:20:
  /data/users/andriin/linux/tools/testing/selftests/bpf/tools/include/bpf/libbpf_legacy.h:113:17: note: by argument 1 of type ‘const void *’ to ‘libbpf_get_error’ declared here
    113 | LIBBPF_API long libbpf_get_error(const void *ptr);
        |                 ^~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors
  make: *** [Makefile:522: /data/users/andriin/linux/tools/testing/selftests/bpf/network_helpers.o] Error 1

This is completely bogus becuase libbpf_get_error() doesn't dereference
pointer, but the only easy way to silence this is to allocate initialized
memory with calloc().

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/testing/selftests/bpf/network_helpers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 59cf81ec55af..bec15558fd93 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -436,7 +436,7 @@ struct nstoken *open_netns(const char *name)
 	int err;
 	struct nstoken *token;
 
-	token = malloc(sizeof(struct nstoken));
+	token = calloc(1, sizeof(struct nstoken));
 	if (!ASSERT_OK_PTR(token, "malloc token"))
 		return NULL;
 
-- 
2.30.2