On Mon, Nov 28, 2022 at 5:29 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Marking following vma objects as trusted so they can be used
> as arguments for kfunc function added in following changes:
>
> - vma object argument in find_vma callback function
> - vma object in context of task_vma iterator program
>
> Both places lock vma object so it can't go away while running
> the bpf program.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> kernel/bpf/task_iter.c | 2 +-
> kernel/bpf/verifier.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
> index c2a2182ce570..cd67b3cadd91 100644
> --- a/kernel/bpf/task_iter.c
> +++ b/kernel/bpf/task_iter.c
> @@ -755,7 +755,7 @@ static struct bpf_iter_reg task_vma_reg_info = {
> { offsetof(struct bpf_iter__task_vma, task),
> PTR_TO_BTF_ID_OR_NULL },
> { offsetof(struct bpf_iter__task_vma, vma),
> - PTR_TO_BTF_ID_OR_NULL },
> + PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
Yonghong, Song,
Do you remember when task or vma is NULL here?
Maybe we can do: if (!task || !vma) skip prog run
in __task_vma_seq_show()
and make both pointers as PTR_TO_BTF_ID | PTR_TRUSTED?
