# Re: \[PATCH v23 22/28\] x86/cet/shstk: User-mode shadow stack support

- From: Borislav Petkov \<bp@alien8.de\>
- Date: 2021-03-19 09:28:46 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2021/03/6307477
- Thread: https://ratatoskr.run/linux-doc/2021/03/6303369/t.md

```text
On Thu, Mar 18, 2021 at 12:05:58PM -0700, Yu, Yu-cheng wrote:
> Maybe I would add comments here.

Yap.

Also, looking forward in the set, I see prctl_set() and that is also
done on current so should be ok.

In any case, yes, documenting the assumptions and expectations wrt
current here is a good idea.

> If vm_munmap() returns -EINTR, mmap_lock is held by something else. That
> lock should not be held forever.  For other types of error, the loop stops.

Ok I guess. The subsequent WARN_ON_ONCE() looks weird too but that
should not fire, right? :)

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette
```