2016-08-03 17:55 GMT+08:00 Radim Krčmář <rkrcmar@xxxxxxxxxx>: > 2016-08-03 12:04+0800, Wanpeng Li: >> From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> >> >> BUG: unable to handle kernel NULL pointer dereference at 000000000000008c >> IP: [<ffffffffc04e0180>] kvm_lapic_hv_timer_in_use+0x10/0x20 [kvm] >> PGD 0 >> Oops: 0000 [#1] SMP >> Call Trace: >> kvm_arch_vcpu_load+0x86/0x260 [kvm] >> vcpu_load+0x46/0x60 [kvm] >> kvm_vcpu_ioctl+0x79/0x7c0 [kvm] >> ? __lock_is_held+0x54/0x70 >> do_vfs_ioctl+0x96/0x6a0 >> ? __fget_light+0x2a/0x90 >> SyS_ioctl+0x79/0x90 >> do_syscall_64+0x7c/0x1e0 >> entry_SYSCALL64_slow_path+0x25/0x25 >> RIP [<ffffffffc04e0180>] kvm_lapic_hv_timer_in_use+0x10/0x20 [kvm] >> RSP <ffff8800db1f3d70> >> CR2: 000000000000008c >> ---[ end trace a55fb79d2b3b4ee8 ]--- >> >> This can be reproduced steadily by kernel_irqchip=off. >> >> We should not access preemption timer stuff if lapic is emulated in userspace. >> This patch fix it by avoiding access preemption timer stuff when kernel_irqchip=off. >> >> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> >> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx> >> Cc: Yunhong Jiang <yunhong.jiang@xxxxxxxxx> >> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> >> --- > > Reviewed-by: Radim Krčmář <rkrcmar@xxxxxxxxxx> > >> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c >> @@ -1348,6 +1348,9 @@ static void start_sw_tscdeadline(struct kvm_lapic *apic) >> >> bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu) > > Btw, the "hv" in makes it look like it has something to do with Hyper-V. > What does "hv" stand for anyway? Hardware Virtualized? Hmm, yeah, hv_timer make people confusing. http://www.spinics.net/lists/kvm/msg134205.html Regards, Wanpeng Li -- 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
