[Bug 218684] CPU soft lockups in KVM VMs on kernel 6.x after switching hypervisor from C8S to C9S

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=218684

--- Comment #4 from Frantisek Sumsal (frantisek@sumsal.cz) ---
(In reply to Sean Christopherson from comment #3)
> Given that 6.7 is still broken, my money is on commit d02c357e5bfa ("KVM:
> x86/mmu: Retry fault before acquiring mmu_lock if mapping is changing"). 
> Ugh, which I neglected to mark for stable.
> 
> Note, if that's indeed what's to blame, there's also a bug in the kernel's
> preemption model logic that is contributing to the problems.
> https://lore.kernel.org/all/20240110214723.695930-1-seanjc@google.com

You're absolutely right. I took the C9S kernel RPM (5.14.0-436), slapped
d02c357e5bfa on top of it, and after running the same tests as in previous
cases all the soft lockups seem to be magically gone. Thanks a lot!

I'll run a couple more tests and if they pass I'll go ahead and sum this up in
a RHEL report, so the necessary patches make it to C9S/RHEL9.

-- 
You may reply to this email to add a comment.

You are receiving this mail because:
You are watching the assignee of the bug.