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

From: Vineet Gupta
Date: Thu Apr 29 2021 - 14:17:30 EST


On 4/29/21 4:39 AM, Shahab Vahedi wrote:
> 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

Thanks for spotting this. I'll fix this up and repush (after the ongoing
merge window).

-Vineet