Re: [PATCH] x86/bhi: BHI mitigation can trigger warning in #DB handler

[Alexandre Chartre]

On 5/23/24 16:28, Dave Hansen wrote:
> On 5/23/24 05:33, Alexandre Chartre wrote:
> > The problem can be reproduced with the following sequence:
> >
> >   $ cat sysenter_step.c
> >   int main()
> >   { asm("pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter"); }
> >
> >   $ gcc -o sysenter_step sysenter_step.c
> >
> >   $ ./sysenter_step
> >   Segmentation fault (core dumped)
> >
> > The program is expected to crash, and the #DB handler will issue a warning.
>
> Should we wrap up this gem and put it with the other entry selftests?

It looks like tools/testing/selftests/x86/single_step_syscall.c tests
sysenter with TF set but it doesn't check if the kernel issues any
warning.

alex.