Messages in this thread | | | From | Linus Torvalds <> | Date | Tue, 4 Apr 2017 17:22:27 -0700 | Subject | Re: sudo x86info -a => kernel BUG at mm/usercopy.c:78! |
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On Tue, Apr 4, 2017 at 3:55 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > > I already explained what the likely fix is: make devmem_is_allowed() > return a ternary value, so that those things that *do* read the BIOS > area can just continue to do so, but they see zeroes for the parts > that the kernel has taken over.
Actually, a simpler solution might be to
(a) keep the binary value
(b) remove the test for the low 1M
(c) to avoid breakage, don't return _error_, but just always read zero
that also removes (or at least makes it much more expensive) a signal of which pages are kernel allocated vs BIOS allocated.
Linus
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