Hello everyone,
I think I brought up this issue before but didn't resolve it completely.
Now I'd like to double check this and if we can agree on it, I'd also
like to submit a patch to fix it. The problem is that function
`get_queue_ctx` can never return a NULL pointer unless pointer overflow
occurs, which is very unlikely. To be more specific,
```
static struct v4l2_m2m_queue_ctx *get_queue_ctx(struct v4l2_m2m_ctx
*m2m_ctx,
enum v4l2_buf_type type)
{
if (V4L2_TYPE_IS_OUTPUT(type))
return &m2m_ctx->out_q_ctx;
else
return &m2m_ctx->cap_q_ctx;
}
```
The address returned by this function is either `(char*)m2m_ctx+968` or
`(char*)m2m_ctx+16`, so for it to be NULL, `m2m_ctx` must be a large
unsigned value. Yet the return value of this function is NULL-checked,
for example in v4l2_m2m_get_vq.
Please let me know if it makes sense.
Best,
Shaobo
