Re: [PATCH 0/3] vmsplice: make vmsplice a trivial wrapper for preadv2/pwritev2

[Linus Torvalds]

On Wed, 3 Jun 2026 at 16:01, Askar Safin <safinaskar@xxxxxxxxx> wrote:
>
> So, if we remove tee(2), then we will probably need to remove all
> non-standard implementations of pipe_buf_operations.

I don't think tee matters.

Sure, it will share pages across pipes.

But if we make normal "splice to pipe" always copy from the page
cache, nobody cares.

You can corrupt the resulting pages as much as you want - through
multiple pipes if you use tee() to copy it - and it's all just
corrupting your private copy.

And yes, iSCSI and nvme might do their own splice-like thing, but
again, nobody really cares. When it's all kernel-internal, the attack
surface has gone away.

So that's why splice() (and vmsplice()) is special - not because it's
buggy, but because it's the user-facing attack surface to expose bugs
elsewhere.

             Linus