Re: [patch 13/26] Xen-paravirt_ops: Consistently wrap paravirt ops callsites to make them patchable

Linus Torvalds
2007-03-20T16:55:17Z

On Tue, 20 Mar 2007, Andi Kleen wrote:
>
> No, me and Jan fixed all reported bugs as far as I know.

No you did not. You didn't fix the ones I reported. Which is why it got
removed, and will not get added back until there is another maintainer.

The ones I reported were all about trusting the stack contents implicitly,
and assuming that the unwind info was there and valid. Using things like
"__get_user()" didn't fix it, because if a WARN_ON() happened while we
held the mm semaphore and the unwind info was bogus, it would take a
page-fault and deadlock.

Those kinds of things are not acceptable for debugging output. If I cannot
use WARN_ON() because I hold the MM lock and I'm afraid there might be
kernel corruption, then something is *wrong*!

And I told you guys this. Over *months*. And you ignored me. You told me
everything was fine. Each time, somebody else ended up reporting a hang
where the unwinder was at fault. And since I couldn't trust the
maintainers to fix it, removing the broken feature that only caused more
problems than it fixed was the only option.

And you clearly *still* haven't accepted the fact that the code was buggy.

Does anybody wonder why I wouldn't merge it back?

Linus