Messages in this thread | | | From | Jann Horn <> | Date | Tue, 28 Aug 2018 01:12:11 +0200 | Subject | Re: [PATCH] x86/nmi: Fix some races in NMI uaccess |
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On Tue, Aug 28, 2018 at 1:04 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.
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?
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