On Tue, Aug 28, 2018 at 1:04 AM Andy Lutomirski <[email protected]> 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.
What about eBPF probes (which I think can be attached to kprobe points / tracepoints / perf events) that perform userspace reads / userspace writes / kernel reads? Can those run in NMI context, and if so, do they also need special handling?
