Re: [RFC] new SYSCALL_DEFINE/COMPAT_SYSCALL_DEFINE wrappers

Linus Torvalds
2018-03-26T06:20:54Z

On Sun, Mar 25, 2018 at 8:15 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> HOWEVER.
>
> I didn't actually test any of the compat or x32 ones, and the way I
> did it there also was no type-checking or other automated catching of
> getting it wrong. So it's almost certainly completely buggy, but the
> _intent_ is there and there is a remote possibility that it might even
> work.

Note: the commit message is "broken, but working, ptregs system call
conversion for x86-64".

The "but working" is not because it would be right, but because it
booted a real 64-bit distribution successfully, and I actually used
that kernel.

But that only tests the native 64-bit case, it in no way tests the
compat or x32 cases what-so-ever. That part was literally a "it
compiles - it must be perfect" with absolutely zero testing of even
the most trivial kind.

And it really would have been most trivial to just do a "Hello world"
and build it with "-m32". I didn't do even that, and if I had, I would
have been honestly surprised had it worked.

But there was a _theoretical_ chance that it could have worked. Maybe.

Linus