Messages in this thread | | | Date | Wed, 7 Aug 2013 12:47:53 -0700 | Subject | Re: [PATCH 0/1] (Was: Linux 3.11-rc4) | From | Linus Torvalds <> |
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On Wed, Aug 7, 2013 at 12:27 PM, Oleg Nesterov <oleg@redhat.com> wrote: > > I guess Grazvydas only meant the "unnecessary" align/len/type checks.
Yeah, some of them may be a bit questionable, but we don't necessarily know what each microarchitecture does for unsupported ("undefined") situations.
Intel actually has a lot of errata for their CPU's that they won't fix, and they tend to be all about exactly the kinds of things that the architecture manuals say "don't do this". Things like "TSS segment crosses a page, and you take a page fault in the middle of a task switch" etc.
Now, I do agree that the debug registers are *much* less likely to have those kinds of really subtle issues, so maybe relaxing some of the tests might be reasonable. I'd be a bit nervous about it, but if it's *only* the length/alignment, and Intel people can be convinced that it doesn't result in any nasty undefined behavior (as long as the address is in user space), maybe we could make that change just to make it easier for Wine.
But the kernel address checking definitely needs to stay around for security reasons.
Linus
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