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Re: [Qemu-devel] [PATCH] hw/hyperv: fix NULL dereference with pure-kvm S
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [Qemu-devel] [PATCH] hw/hyperv: fix NULL dereference with pure-kvm SynIC |
Date: |
Mon, 26 Nov 2018 17:04:37 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 |
On 26/11/18 16:28, Roman Kagan wrote:
> When started in compat configuration of SynIC, e.g.
>
> qemu-system-x86_64 -machine pc-i440fx-2.10,accel=kvm \
> -cpu host,-vmx,hv-relaxed,hv_spinlocks=0x1fff,hv-vpindex,hv-synic
>
> or explicitly
>
> qemu-system-x86_64 -enable-kvm -cpu host,hv-synic,x-hv-synic-kvm-only=on
>
> QEMU crashes in hyperv_synic_reset() trying to access the non-present
> qobject for SynIC.
>
> Add the missing check for NULL.
>
> Reported-by: Vitaly Kuznetsov <address@hidden>
> Reported-by: Igor Mammedov <address@hidden>
> Fixes: 9b4cf107b09d18ac30f46fd1c4de8585ccba030c
> Fixes: 4a93722f9c279184e95b1e1ad775c01deec05065
> Signed-off-by: Roman Kagan <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
Tested-by: Philippe Mathieu-Daudé <address@hidden>
> ---
> hw/hyperv/hyperv.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/hw/hyperv/hyperv.c b/hw/hyperv/hyperv.c
> index a28e7249d8..8758635227 100644
> --- a/hw/hyperv/hyperv.c
> +++ b/hw/hyperv/hyperv.c
> @@ -136,7 +136,11 @@ void hyperv_synic_add(CPUState *cs)
>
> void hyperv_synic_reset(CPUState *cs)
> {
> - device_reset(DEVICE(get_synic(cs)));
> + SynICState *synic = get_synic(cs);
> +
> + if (synic) {
> + device_reset(DEVICE(synic));
> + }
> }
>
> static const TypeInfo synic_type_info = {
>