Re: [PATCH] tracing/user_events: Run BPF program if attached

[Steven Rostedt]

On Tue, 16 May 2023 18:46:29 -0700
Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> So don't even ask for other GUP functionality, much less the "remote"
> kind. Not going to happen. If you think you need access to remote
> process memory, you had better do it in process context, or you had
> better just think again.

So this code path is very much in user context (called directly by a
write system call). The issue that Alexei had was that it's also in an
rcu_read_lock() section.

I wonder if this all goes away if we switch to SRCU? That is, sleepable RCU.

-- Steve