On Wed, Jan 15, 2020 at 09:24:28AM -0400, Jason Gunthorpe wrote: > I was interested because you are talking about allowing the read/write side > of a rw sem to be held across a return to user space/etc, which is the > same basic problem. No it is not; allowing the lock to be held across userspace doesn't change the owner. This is a crucial difference, PI depends on there being a distinct owner. That said, allowing the lock to be held across userspace still breaks PI in that it completely wrecks the ability to analyze the critical section.
