Re: [PATCH 3/4] mmap locking API: Don't check locking if the mm isn't live yet

Jason Gunthorpe
2020-09-30T12:30:05Z

On Tue, Sep 29, 2020 at 06:20:00PM -0700, Jann Horn wrote:
> In preparation for adding a mmap_assert_locked() check in
> __get_user_pages(), teach the mmap_assert_*locked() helpers that it's fine
> to operate on an mm without locking in the middle of execve() as long as
> it hasn't been installed on a process yet.

I'm happy to see lockdep being added here, but can you elaborate on
why add this mmap_locked_required instead of obtaining the lock in the
execv path?

Jason