On Wed, Dec 16, 2020 at 06:07:48AM +0100, Jann Horn wrote:
> On Wed, Dec 16, 2020 at 5:47 AM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> 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.
> >
> > Existing code paths that do this are (reverse callgraph):
> >
> > get_user_pages_remote
> > get_arg_page
> > copy_strings
> > copy_string_kernel
> > remove_arg_zero
> > tomoyo_dump_page
> > tomoyo_print_bprm
> > tomoyo_scan_bprm
> > tomoyo_environ
>
> Sorry, can you please kill both this patch and the following one
> ("mm/gup: assert that the mmap lock is held in __get_user_pages()")
> from the mm tree?
>
> I'll send new stuff (a new iteration of
> https://lore.kernel.org/linux-mm/20201016225713.1971256-1-jannh@xxxxxxxxxx/
> "[PATCH resend v3 0/2] Broad write-locking of nascent mm in execve",
> followed by a resend of "mm/gup: assert that the mmap lock is held in
> __get_user_pages()") when it's ready.
I'm glad you are still working on it, I think finally being able to
add lockdep to get_user_pages will be a help. I've fixed a number of
wrongly locked get_user_pages users :(
Thanks,
Jason
