On Fri, Jun 17, 2016 at 01:00:39PM -0700, Andy Lutomirski wrote: > It's currently only used in the EFI code, which is safe AFAICT.
"It is basically useful for a pagetable hierarchy which is not init_mm." > Warn if anyone tries to use it on the normal kernel pgd. > > Signed-off-by: Andy Lutomirski <[email protected]> > --- > arch/x86/mm/pageattr.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c > index 6a8026918bf6..e9b9c5cedbb8 100644 > --- a/arch/x86/mm/pageattr.c > +++ b/arch/x86/mm/pageattr.c > @@ -1996,6 +1996,9 @@ out: > void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address, > unsigned numpages) > { > + /* Unmapping kernel entries from init_mm's pgd is not allowed. */ > + WARN_ON(root == init_mm.pgd); We can also return and not do the unmapping: if (WARN_ON(root == init_mm.pgd)) return; -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.
