at 8:47 AM, Andy Lutomirski <luto@xxxxxxxxxx> 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@xxxxxxxxxxxxxxx > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Nadav Amit <nadav.amit@xxxxxxxxx> > Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> > --- > > 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
