Messages in this thread | | | Subject | Re: [PATCH v2] x86/nmi: Fix some races in NMI uaccess | From | Nadav Amit <> | Date | Wed, 29 Aug 2018 11:56:08 -0700 |
| |
at 8:47 AM, Andy Lutomirski <luto@kernel.org> wrote:
> In NMI context, we might be in the middle of context switching or in > the middle of switch_mm_irqs_off(). In either case, CR3 might not > match current->mm, which could cause copy_from_user_nmi() and > friends to read the wrong memory. > > Fix it by adding a new nmi_uaccess_okay() helper and checking it in > copy_from_user_nmi() and in __copy_from_user_nmi()'s callers. > > Cc: stable@vger.kernel.org > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Nadav Amit <nadav.amit@gmail.com> > Signed-off-by: Andy Lutomirski <luto@kernel.org> > --- > > Nadav, this is intended for your series. Want to add it right > before the use_temporary_mm() stuff?
Sure. Thanks! I will apply the following small fix:
> + > +#ifdef CONFIG_DEBUG_VM > + WARN_ON_ONCE(!loaded_mm); > +#endif
Will be changed to VM_WARN_ON_ONCE() in the two instances.
Regards, Nadav
| |