2017-04-26 16:29+0200, Paolo Bonzini: > 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) We called rcu_irq_enter() there twice, *facepalm*. Yes, that patch should fix it.
