On 26/04/2017 16:18, Radim Krčmář wrote: >> OK, but looking at the stack trace, this has nothing to do with ext4. The >> problem seems to be in KVM - relevant CCs added. > The path begins with async_page_fault interrupt gate and the hardware > should clear the interrupt flag before executing it. I don't see a > change that would break the assumption that interrupts are disabled ... native_safe_halt enables interrupts. I think this is it: diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 14f65a5f938e..2a7835932b71 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -161,8 +161,8 @@ void kvm_async_pf_task_wait(u32 token) */ rcu_irq_exit(); native_safe_halt(); - rcu_irq_enter(); local_irq_disable(); + rcu_irq_enter(); } } if (!n.halted) Paolo
