Messages in this thread | | | Date | Tue, 3 Nov 2020 19:20:18 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v2] x86/dumpstack: Fix misleading instruction pointer error message |
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On Tue, Nov 03, 2020 at 07:11:15PM +0100, Oleg Nesterov wrote: > > I'm thinking copy_code() should not use copy_from_user_nmi() if former > > can be called in non-atomic context too. > > I understand, but why do you think this makes sense?
Because the copy_from_user_nmi()'s name tells me that it is at least supposed to be called in atomic context. At least this is how I understand it. And in atomic context regs is supposed to belong to current, right?
So I kinda agree with what you're proposing but if copy_from_user_nmi() can be "tricked" into reading off from the weeds, then there should be a big fat warning above it at least so that users are warned to do the appropriate checks.
Or there should be another wrapper around it which does the regs-belongs-to-current checks, etc and copy_code() should use that wrapper...
AFAICT at least.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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