On Mon, Jul 18, 2011 at 9:18 PM, Berg, Johannes <johannes.berg@xxxxxxxxx> wrote: >> Today I encountered a "BUG: scheduling while atomic" from kvm.ko when >> resuming the host from suspend-to-RAM. I captured as much of the oops as >> was displayed on screen: >> >> http://vmsplice.net/~stefan/panic1.jpg >> http://vmsplice.net/~stefan/panic2.jpg >> >> It looks like the iwlagn driver may have crashed in an interrupt handler and the >> kvm-related panic was triggered in the aftermath. Any ideas? > > This doesn't look like iwlagn is involved at all -- the fact that it comes up in the backtrace seems to be an artifact of backtracing not being perfect. The RIP points to kvm_arch_vcpu_ioctl_run+0x927 and there's no reason to believe that iwlagn should crash kvm. RIP seems to be arch/x86/kvm/x86.c:vcpu_enter_guest(): preempt_disable(); kvm_x86_ops->prepare_guest_switch(vcpu); if (vcpu->fpu_active) kvm_load_guest_fpu(vcpu); kvm_load_guest_xcr0(vcpu); vcpu->mode = IN_GUEST_MODE; /* We should set ->mode before check ->requests, * see the comment in make_all_cpus_request. */ smp_mb(); local_irq_disable(); if (vcpu->mode == EXITING_GUEST_MODE || vcpu->requests || need_resched() || signal_pending(current)) { vcpu->mode = OUTSIDE_GUEST_MODE; smp_wmb(); local_irq_enable(); preempt_enable(); kvm_x86_ops->cancel_injection(vcpu); r = 1; goto out; } srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); kvm_guest_enter(); if (unlikely(vcpu->arch.switch_db_regs)) { set_debugreg(0, 7); set_debugreg(vcpu->arch.eff_db[0], 0); set_debugreg(vcpu->arch.eff_db[1], 1); set_debugreg(vcpu->arch.eff_db[2], 2); set_debugreg(vcpu->arch.eff_db[3], 3); } trace_kvm_entry(vcpu->vcpu_id); kvm_x86_ops->run(vcpu); /* * If the guest has used debug registers, at least dr7 * will be disabled while returning to the host. * If we don't have active breakpoints in the host, we don't * care about the messed up debug address registers. But if * we have some of them active, restore the old state. */ if (hw_breakpoint_active()) hw_breakpoint_restore(); kvm_get_msr(vcpu, MSR_IA32_TSC, &vcpu->arch.last_guest_tsc); vcpu->mode = OUTSIDE_GUEST_MODE; smp_wmb(); local_irq_enable(); /* <--- boom! */ Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
