On Wed, Jul 30, 2025 at 2:59 PM Amery Hung <ameryhung@xxxxxxxxx> wrote:
>
> Allow syscall programs to call non-recur helpers too since syscall bpf
> programs runs in process context through bpf syscall, BPF_PROG_TEST_RUN,
> and cannot run recursively.
>
> bpf_task_storage_{get,set} have "_recur" versions that call trylock
> instead of taking the lock directly to avoid deadlock when called by
> bpf programs that run recursively. Currently, only bpf_lsm, bpf_iter,
> struct_ops without private stack are allow to call the non-recur helpers
> since they cannot be recursively called in another bpf program.
>
> Signed-off-by: Amery Hung <ameryhung@xxxxxxxxx>
Re-adding the tags in the case this is the final version, as we
discussed off-list.
Reviewed-by: Emil Tsalapatis <emil@xxxxxxxxxxxxxxx>
> ---
> include/linux/bpf_verifier.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
> index 94defa405c85..c823f8efe3ed 100644
> --- a/include/linux/bpf_verifier.h
> +++ b/include/linux/bpf_verifier.h
> @@ -962,6 +962,7 @@ static inline bool bpf_prog_check_recur(const struct bpf_prog *prog)
> case BPF_PROG_TYPE_STRUCT_OPS:
> return prog->aux->jits_use_priv_stack;
> case BPF_PROG_TYPE_LSM:
> + case BPF_PROG_TYPE_SYSCALL:
> return false;
> default:
> return true;
> --
> 2.47.3
>
