On Tue, Feb 11, 2025, Rick P Edgecombe wrote: > On Tue, 2025-02-11 at 09:42 +0800, Yan Zhao wrote: > > > On the fix though, doesn't this remove the coverage of writing to a > > > region that is in the process of being made RO? I'm thinking about > > > warnings, etc that may trigger intermittently based on bugs with a race > > > component. I don't know if we could fix the test and still leave the > > > write while the "mprotect(PROT_READ) is underway". It seems to be > > > deliberate. > > Write before "mprotect(PROT_READ)" has been tested in stage 0. > > Not sure it's deliberate to test write in the process of being made RO. Writing while VMAs are being made RO is 100% intended. The goal is to stress KVM's interactions with the mmu_notifier, and to verify KVM delivers -EFAULT to userspace. Something isn't quite right in the original analysis. We need to drill down on that before change anything. FWIW, I run this test frequently on large systems and have never observed failures. Maybe Rick and I should go buy lottery tickets?
