Re: [5.2 REGRESSION] Generic vDSO breaks seccomp-enabled userspace on i386

[Andy Lutomirski]

> On Jul 23, 2019, at 2:18 AM, Peter Zijlstra <pet...@infradead.org> wrote:
> 
>> On Mon, Jul 22, 2019 at 04:47:36PM -0700, Andy Lutomirski wrote:
>> 
>> I don't love this whole concept, but I also don't have a better idea.
> 
> Are we really talking about changing the kernel because BPF is expecting
> things? That is, did we just elevate everything BPF can observe to ABI?
> 

No, this isn’t about internals in the kernel mode sense. It’s about the 
smallish number of cases where the kernel causes user code to do a specific 
syscall and the user has a policy that doesn’t allow that syscall.  This is 
visible to user code via seccomp and ptrace.

Yes, it’s obnoxious.  Do you have any suggestions?