Hi Alexei, On Thu, Nov 17, 2022 at 08:50:12AM -0800, Alexei Starovoitov wrote: > There might not be a task available where bpf trampoline is running. I'm not sure what you mean by "there might not be a task available"; do you mean that there might not be space in the per-task shadow stack, or that the BPF program can be invoked inan IRQ context? > rcu protection might not be there either. We've spent a lot of time reworking entry/idle sequences with noinstr, so any time BPF can be invoked, we should have a regular kernel environment available, with RCU watching (but not necessarily in an RCU read-side critical section). If BPF is being invoked without RCU watching, that is a bug that needs to be fixed. Do you have a specific example in mind? Thanks, Mark.
