Re: [PATCH v3 bpf-next 02/18] bpf: Add bpf_arch_text_poke() helper

On Thu, Nov 07, 2019 at 10:40:23PM -0800, Alexei Starovoitov wrote:

Add bpf_arch_text_poke() helper that is used by BPF trampoline logic to patch
nops/calls in kernel text into calls into BPF trampoline and to patch
calls/nops inside BPF programs too.

This thing assumes the text is unused, right? That isn't spelled out
anywhere. The implementation is very much unsafe vs concurrent execution
of the text.