On 4/16/21 5:43 PM, Oleg Nesterov wrote:
 On 04/16, He Zhe wrote:
> --- a/arch/arm64/include/asm/syscall.h
> +++ b/arch/arm64/include/asm/syscall.h
> @@ -44,7 +44,12 @@ static inline long syscall_get_error(struct task_struct *task,
>  static inline long syscall_get_return_value(struct task_struct *task,
>  					    struct pt_regs *regs)
>  {
> -	return regs->regs[0];
> +	long val = regs->regs[0];
> +
> +	if (is_compat_thread(task_thread_info(task)))
> +		val = sign_extend64(val, 31);
> +
> +	return val;
>  }
 I can't really review these arm-specific patches, but with this change both
 syscall_get_error() and is_syscall_success() can use syscall_get_return_value()
 to avoid the code duplication. 
Thanks. I'll improve this if v2 is needed.
Regards,
Zhe
 Oleg.