Re: [RFC] fixing the UML failure root cause

[Linus Torvalds]

On Wed, Oct 12, 2011 at 5:24 AM, Andrew Lutomirski <luto@xxxxxxx> wrote:
>
> So here's a different approach.  It's not perfect: it always blames
> SEGV_MAPERR instead of SEGV_ACCERR.  I implemented it for vgettimeofday
> but not the other two vsyscalls.
>
> What do you think of this approach?  If it seems good, I'll finish the
> patch and submit it.

I think the approach is valid, but you should *not* do this as some
kind of crazy byte-by-byte copy_to_user() emulation.

Do the "copy tz to user mode" as individual "put_user()" calls for
tv_sec/tv_usec/timezone. IOW, there are three words being written to
user mode, not "two memcpy's".

Other than that, there doesn't seem to be anything wrong.

            Linus
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