Re: [lockdep] b09be676e0 BUG: unable to handle kernel NULL pointer dereference at 000001f2

From: Linus Torvalds
Date: Tue Oct 03 2017 - 12:57:09 EST

On Tue, Oct 3, 2017 at 9:54 AM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> Can we consider just reverting the crossrelease thing?
> The apparent stack corruption really worries me [...]

Side note: I also think the thing is just broken.

Any actual cross-releaser should be way more annotated than just "set
cross to 1" in the lockdep map.

The place where the release is done should simply be special.

Because we should *not* encourage the whole "acquire by one context,
release by another" as being something normal and "just set the flag
to let lockdep know".

So that commit is apparently buggy, but I think it might be more
fundamentally the wrong model too.