Re: [PATCH] kernel/kmod: fix use-after-free of the sub_infostructure

[Oleg Nesterov]

On 10/17, Martin Schwidefsky wrote:
>
> On Thu, 16 Oct 2014 23:58:34 +0200
> Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
>
> > I also agree that the changelog could mention exec_mmap. Plus a comment
> > about UMH_NO_WAIT && sub_info->complete == NULL. So yes, perhaps v2 makes
> > sense if Martin agrees.
>
> Version 2 of the patch.

Thanks!

> All change requests have gone in except for the
> mention of exec_mmap. I don't quite get the relevance of it, do_execve
> can fail for the various reasons.

Yes. But if it fails before exec_mmap() (which in particular calls
mm_release()->complete_vfork_done()) we are safe; sub_info can't go away
because the parent sleeps in sys_wait4() if UMH_WAIT_PROC, or it sleeps
in wait_for_vfork_done() otherwise.

But this is minor, and this only relates to the changelog. So still/again

Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>

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