[CRIU] [PATCH 5/8] parasite: restore registers after each parasite command

[Pavel Emelyanov]

On 07/11/2013 01:46 PM, Andrey Vagin wrote:
> Currenly we can restore blocking signals with help ptrace,
> so if registers are restored after command, a process state
> will not be corrupted if criu crashes.

If criu crashes the sigreturn rescue code will restore the regs. No?

> Signed-off-by: Andrey Vagin <avagin at openvz.org>
> ---
>  parasite-syscall.c | 19 +++++++------------
>  1 file changed, 7 insertions(+), 12 deletions(-)
> 
> diff --git a/parasite-syscall.c b/parasite-syscall.c
> index 2b9877c..07b45bc 100644
> --- a/parasite-syscall.c
> +++ b/parasite-syscall.c
> @@ -84,7 +84,7 @@ int __parasite_execute_trap(struct parasite_ctl *ctl, pid_t pid,
>  
>  	if (ptrace(PTRACE_SETREGS, pid, NULL, regs)) {
>  		pr_perror("Can't set registers (pid: %d)", pid);
> -		goto err;
> +		goto err_sigmask;
>  	}
>  
>  	/*
> @@ -130,7 +130,13 @@ int __parasite_execute_trap(struct parasite_ctl *ctl, pid_t pid,
>  	 * parasite code. So we're done.
>  	 */
>  	ret = 0;
> +
>  err:
> +	if (ptrace(PTRACE_SETREGS, pid, NULL, regs_orig)) {
> +		pr_perror("Can't restore registers (pid: %d)", pid);
> +		ret = -1;
> +	}
> +err_sigmask:
>  	if (ptrace(PTRACE_SETSIGMASK, pid, sizeof(k_rtsigset_t), &sigmask)) {
>  		pr_perror("Can't block signals");
>  		ret = -1;
> @@ -164,12 +170,6 @@ static int parasite_execute_trap_by_pid(unsigned int cmd,
>  	if (ret)
>  		pr_err("Parasite exited with %d\n", ret);
>  
> -	if (ctl->pid.real != pid)
> -		if (ptrace(PTRACE_SETREGS, pid, NULL, regs_orig)) {
> -			pr_perror("Can't restore registers (pid: %d)", pid);
> -			return -1;
> -		}
> -
>  	return ret;
>  }
>  
> @@ -864,11 +864,6 @@ int parasite_cure_remote(struct parasite_ctl *ctl)
>  		ret = -1;
>  	}
>  
> -	if (ptrace(PTRACE_SETREGS, ctl->pid.real, NULL, &ctl->regs_orig)) {
> -		pr_err("Can't restore registers (pid: %d)\n", ctl->pid.real);
> -		ret = -1;
> -	}
> -
>  	return ret;
>  }
>  
>