Re: [PATCH bpf-next v1 13/14] selftests/bpf: Fix out-of-bounds array access bugs reported by ASAN

[Ihor Solodrai]

On 2/12/26 5:11 PM, Eduard Zingerman wrote:
> On Wed, 2026-02-11 at 17:13 -0800, Ihor Solodrai wrote:
>> - kmem_cache_iter: remove unnecessary debug output
>> - lwt_seg6local: change the type of foobar to char[]
>>   - the sizeof(foobar) returned the pointer size and not a string
>>     length as intended
>> - verifier_log: increase prog_name buffer size in verif_log_subtest()
>>   - compiler has a conservative estimate of fixed_log_sz value, making
>>     ASAN complain on snprint() call
>>
>> Signed-off-by: Ihor Solodrai <ihor.solodrai@xxxxxxxxx>
>> ---
> 
> Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
> 
> [...]
> 
>> diff --git a/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c
>> b/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c
>> index 6e35e13c2022..399fe9103f83 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c
>> @@ -104,11 +104,8 @@ void test_kmem_cache_iter(void)
>>  	if (!ASSERT_GE(iter_fd, 0, "iter_create"))
>>  		goto destroy;
>>  
>> -	memset(buf, 0, sizeof(buf));
>> -	while (read(iter_fd, buf, sizeof(buf)) > 0) {
>> -		/* Read out all contents */
>> -		printf("%s", buf);
>> -	}
>> +	while (read(iter_fd, buf, sizeof(buf)) > 0)
>> +		; /* Read out all contents */
> 
> Nit:
>   -       while (read(iter_fd, buf, sizeof(buf)) > 0) {
>   +       while (read(iter_fd, buf, sizeof(buf) - 1) > 0) {
> 
>   And keep the log?

AFAIU it's not necessary for the test, it seems to be a debug print.

There is an exact copy of this loop without printf in dmabuf_iter.c.

> 
> [...]