Re: [PATCH] ARC: entry: fix off-by-one error in syscall number validation

[Shahab Vahedi]

On 4/23/21 9:52 PM, Vineet Gupta wrote:
> diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
> index 1743506081da..aea9b558993d 100644
> --- a/arch/arc/kernel/entry.S
> +++ b/arch/arc/kernel/entry.S
> @@ -255,7 +255,7 @@ ENTRY(EV_Trap)
>  	;============ Normal syscall case
>  
>  	; syscall num shd not exceed the total system calls avail
> -	cmp     r8,  NR_syscalls
> +	cmp     r8,  NR_syscalls - 1
>  	mov.hi  r0, -ENOSYS
>  	bhi     .Lret_from_system_call

Same problem exists in "syscall Tracing" section:

; Do the Sys Call as we normally would.
; Validate the Sys Call number
cmp     r8,  NR_syscalls
mov.hi  r0, -ENOSYS
bhi     tracesys_exit


-- 
Shahab