On Mon, Jul 22, 2024 at 5:50 PM Kumar Kartikeya Dwivedi
[off-list ref] wrote:

quoted

  > Currently we cannot pass the pointer returned by the iterator next
  > method as argument to the KF_TRUSTED_ARGS kfuncs, because the pointer
  > returned by the iterator next method is not "valid".

I've replied to this particular patch to explain what exact unsafety
it might introduce.

What do you mean?
I think we can make the return value from iter_next() trusted in
certain cases.
For example bpf_iter_task_next() returns task_struct and it
can be safely marked as MEM_RCU, since the whole iterator is
KF_RCU_PROTECTED.