Subject: Re: [PATCH 1/3] uprobes: add trap variant helper

From: Oleg Nesterov <[email-masked]>
Date: Fri, 22 Mar 2013 15:54:06 +0100

On 03/22, Ananth N Mavinakayanahalli wrote:
>
> +/**
> + * is_trap_insn - check if instruction is breakpoint instruction.
> + * @insn: instruction to be checked.
> + * Default implementation of is_trap_insn
> + * Returns true if @insn is a breakpoint instruction.
> + *
> + * This function is needed for the case where an architecture has multiple
> + * trap instructions (like powerpc).
> + */
> +bool __weak is_trap_insn(uprobe_opcode_t *insn)
> +{
> +	return is_swbp_insn(insn);
> +}

OK, thanks, the whole series looks fine, just one note...

My patch also changed prepare_uprobe() to use is_trap_insn(), and I think
this is right. Exactly because of 3/3 which removes is_trap() from
arch_uprobe_analyze_insn().

If the original insn is_trap(), we do not want to singlestep it and get
another trap after we hit handle_swbp().

Oleg.