selftests/bpf: Fix incorrect parameters in NULL pointer checking

From: Hao Ge <[email protected]>

Smatch reported the following warning:
./tools/testing/selftests/bpf/testing_helpers.c:455 get_xlated_program()
warn: variable dereferenced before check 'buf' (see line 454)

It seems correct,so let's modify it based on it's suggestion.

Actually,commit b23ed4d74c4d ("selftests/bpf: Fix invalid pointer check in get_xlated_program()") fixed an issue in the test_verifier.c once,but it was reverted this time.

Let's solve this issue with the minimal changes possible.

---
 tools/testing/selftests/bpf/testing_helpers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index d5379a0e6da8..34dfea295c8e 100644
@@ -451,7 +451,7 @@ int get_xlated_program(int fd_prog, struct bpf_insn **buf, __u32 *cnt)
 
 	*cnt = xlated_prog_len / buf_element_size;
 	*buf = calloc(*cnt, buf_element_size);
-	if (!buf) {
+	if (!*buf) {
 		perror("can't allocate xlated program buffer");
 		return -ENOMEM;
 	}

2.25.1

Hi

I apologize for the confusion.

 I mistakenly thought that my previous email (https://lore.kernel.org/all/[email protected]/)

didn't send due to network issues on my computer, so I resent it.

However, it seems that was not the case.

Please kindly disregard this patch as it is identical to the previous one.

I sincerely apologize for wasting everyone's time