Re: [patch V6 06/11] rseq: Implement syscall entry work for time slice extensions

From: Thomas Gleixner

Date: Thu Dec 18 2025 - 17:28:50 EST


On Tue, Dec 16 2025 at 10:05, Mathieu Desnoyers wrote:
> On 2025-12-15 13:24, Thomas Gleixner wrote:
> [...]
>>
>> If the code detects inconsistent user space that result in a SIGSEGV for
>> the application.
>
> With these last updates that allow userspace to call arbitrary system
> calls to terminate the grant, the only scenario which triggers SIGSEGV
> is if the put_user() storing to the rseq area fails. Perhaps we should

Nope. There is also the debug path which will catch offenders which
fiddle with the state.

Thanks,

tglx