Re: [PATCH 1/2 v2] kprobe: Do not use uaccess functions to access kernel memory that can fault

[Andy Lutomirski]

On Sat, Feb 23, 2019 at 4:44 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> On Sat, 23 Feb 2019 12:47:46 +0900
> Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
>
> > Since kprobes handler runs in IRQ context, we can not use access_ok() in it.
> > (only on x86 + CONFIG_DEBUG_ATOMIC_SLEEP=y)
>
> Is it really IRQ context or exception context? That is, one
> (interrupts) happen for any task, but exceptions happen because of the
> software that is executed (like a breakpoint). Although you can have a
> kprobe trigger in an interrupt handler (where user access wouldn't make
> sense anyway). But there should be no problem with user access from an
> exception handler.
>

Can we just get rid of this might_sleep()?  access_ok() doesn't sleep
as far as I know.