On 17/12/18 03:43, Wanpeng Li wrote: > From: Wanpeng Li <[email protected]> > > Reported by syzkaller: > > CPU: 1 PID: 5962 Comm: syz-executor118 Not tainted 4.20.0-rc6+ #374 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:kvm_apic_hw_enabled arch/x86/kvm/lapic.h:169 [inline] > RIP: 0010:vcpu_scan_ioapic arch/x86/kvm/x86.c:7449 [inline] > RIP: 0010:vcpu_enter_guest arch/x86/kvm/x86.c:7602 [inline] > RIP: 0010:vcpu_run arch/x86/kvm/x86.c:7874 [inline] > RIP: 0010:kvm_arch_vcpu_ioctl_run+0x5296/0x7320 arch/x86/kvm/x86.c:8074 > Call Trace: > kvm_vcpu_ioctl+0x5c8/0x1150 > arch/x86/kvm/../../../virt/kvm/kvm_main.c:2596 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:509 [inline] > do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 > __do_sys_ioctl fs/ioctl.c:720 [inline] > __se_sys_ioctl fs/ioctl.c:718 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The reason is that the testcase writes hyperv synic HV_X64_MSR_SINT14 msr > and triggers scan ioapic logic to load synic vectors into EOI exit bitmap. > However, irqchip is not initialized by this simple testcase, ioapic/apic > objects should not be accessed. > > This patch fixes it by also considering whether or not apic is present. > > Reported-by: [email protected] > Cc: Paolo Bonzini <[email protected]> > Cc: Radim Krčmář <[email protected]> > Signed-off-by: Wanpeng Li <[email protected]> > --- > arch/x86/kvm/x86.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 4f786fc..c7c1197 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -7510,7 +7510,7 @@ void kvm_make_scan_ioapic_request(struct kvm *kvm) > > static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) > { > - if (!kvm_apic_hw_enabled(vcpu->arch.apic)) > + if (!kvm_apic_present(vcpu)) > return; > > bitmap_zero(vcpu->arch.ioapic_handled_vectors, 256); >
Queued, thanks. Paolo
