Re: [PATCH 1/2] uprobes/x86: Change __skip_sstep() to actually skip the whole insn

[Srikar Dronamraju <srikar@linux.vnet.ibm.com>]

* Oleg Nesterov <oleg@redhat.com> [2012-12-30 16:47:19]:

> __skip_sstep() doesn't update regs->ip. Currently this is correct
> but only "by accident" and it doesn't skip the whole insn. Change
> it to advance ->ip by the length of the detected 0x66*0x90 sequence.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

> ---
>  arch/x86/kernel/uprobes.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
> index c71025b..4e33a35 100644
> --- a/arch/x86/kernel/uprobes.c
> +++ b/arch/x86/kernel/uprobes.c
> @@ -680,8 +680,11 @@ static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
>  		if (auprobe->insn[i] == 0x66)
>  			continue;
> 
> -		if (auprobe->insn[i] == 0x90)
> +		if (auprobe->insn[i] == 0x90) {
> +			regs->ip = uprobe_get_swbp_addr(regs);
> +			regs->ip += i + 1;
>  			return true;
> +		}
> 
>  		break;
>  	}
> -- 
> 1.5.5.1
>