Re: [PATCH 2/2] uprobes: x86: Prohibit probing on MOV SS instruction

Oleg Nesterov
2018-05-09T16:39:45Z

On 05/09, Masami Hiramatsu wrote:
>
> Since MOV SS and POP SS instructions will delay the exceptions
> until the next instruction is executed, we should not do
> single-stepping on it by uprobes.
...
> --- a/arch/x86/kernel/uprobes.c
> +++ b/arch/x86/kernel/uprobes.c
> @@ -299,6 +299,10 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool
> if (is_prefix_bad(insn))
> return -ENOTSUPP;
>
> + /* We should not singlestep on the exception masking instructions */
> + if (insn_masking_exception(insn))
> + return -ENOTSUPP;

Acked-by: Oleg Nesterov <oleg@redhat.com>