Re: [PATCH] libbpf:fix use empty function pointers in ringbuf_poll

[zhangmingyi]

On 06/06,Stanislav Fomichev wrote:

> On 06/05, Xin Liu wrote:
> > From: zhangmingyi <zhangmingyi5@xxxxxxxxxx>
> 
> > The sample_cb of the ring_buffer__new interface can transfer NULL. However,
> > the system does not check whether sample_cb is NULL during 
> > ring_buffer__poll, null pointer is used.

> What is the point of calling ring_buffer__new with sample_cb == NULL?

Yes, as you said, passing sample_cb in ring_buffer__new to NULL doesn't 
make sense, and few people use it that way, but that doesn't prevent this 
from being a allowed and supported scenario. And when ring_buffer__poll is 
called, it leads to a segmentation fault (core dump), which I think needs 
to be fixed to ensure the security quality of libbpf.