Re: [PATCH 1/2] x86/uprobes: Keep shadow stack in sync for emulated CALLs

[David Windsor]

On Tue, Jun 23, 2026 at 4:43 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Mon, Jun 22, 2026 at 02:31:08PM -0400, David Windsor wrote:
> > Uprobe CALL emulation updates the normal user stack, but not the CET user
> > shadow stack. The subsequent RET then sees a stale shadow stack entry and
> > raises #CP.
> >
> > Update the relative CALL emulation and XOL CALL fixup paths to keep the
> > shadow stack in sync.
> >
> > Fixes: 488af8ea7131 ("x86/shstk: Wire in shadow stack interface")
>
> I can confirm this patch fixes the included test case, so yay for that.
>
> However, should this not be:
>
> Fixes: 1713b63a07a2 ("x86/shstk: Make return uprobe work with shadow stack")
>
> ?
>

Hmm, this commit appears to only be concerned with the uretprobe case?