Re: [PATCH v2 4/4] uprobes/powerpc: Make use of generic routines to enable single step

[Oleg Nesterov <oleg@redhat.com>]

On 12/03, Suzuki K. Poulose wrote:
>
> Replace the ptrace helpers with the powerpc generic routines to
> enable/disable single step. We save/restore the MSR (and DCBR for BookE)
> across for the operation. We don't have to disable the single step,
> as restoring the MSR/DBCR would restore the previous state.

Obviously I can't review this series (although it looks fine to me).

Just one note,

> @@ -121,7 +132,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
>
>  	WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
>
> -	uprobe_restore_context_sstep(&utask->autask);
> +	uprobe_restore_context_sstep(&utask->autask, regs);

I am not sure ppc needs this, but note that x86 does a bit more.

Not only we need to restore the "single-step" state, we need to
send SIGTRAP if it was not set by us. The same for _skip_sstep.

But even if I am right I do not suggest to change this series,
this can be done as a separate patch.

Oleg.