Re: [PATCH bpf-next v2 3/4] selftests/bpf: impose global ordering for test decl_tags

[Puranjay Mohan <puranjay@kernel.org>]

bot+bpf-ci@kernel.org writes:

>> diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c
>> index 50ca1b6ec8150..3f784cc76f8f5 100644
>> --- a/tools/testing/selftests/bpf/test_loader.c
>> +++ b/tools/testing/selftests/bpf/test_loader.c
>
> [ ... ]
>
>> +static const char **collect_decl_tags(struct btf *btf, int id, int *cnt)
>> +{
>> +	const char **tmp, **tags = NULL;
>> +	const struct btf_type *t;
>> +	int i;
>> +
>> +	*cnt = 0;
>> +	for (i = 1; i < btf__type_cnt(btf); i++) {
>> +		t = btf__type_by_id(btf, i);
>> +		if (!btf_is_decl_tag(t) || t->type != id || btf_decl_tag(t)->component_idx != -1)
>> +			continue;
>> +		tmp = realloc(tags, (*cnt + 1) * sizeof(*tags));
>> +		if (!tmp) {
>> +			free(tmp);
>> +			return ERR_PTR(-ENOMEM);
>> +		}
>
> Should free(tmp) be free(tags) here? When realloc fails, tmp is NULL,
> so free(tmp) is a no-op. The previously allocated tags array would be
> leaked.
>

This is correct, realloc() will return NULL on failure, we should do free(tags)