Re: [PATCH 5/5] accel/kvm: Fix SIGSEGV when execute "query-balloon" after CPR transfer

[Steven Sistare <steven.sistare@oracle.com>]

On 9/25/2025 10:25 PM, Zhenzhong Duan wrote:
> After CPR transfer, source QEMU close kvm fd and free kvm_state,
> "query-balloon" will check kvm_state->sync_mmu and trigger NULL
> pointer reference.
> 
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>

Reviewed-by: Steve Sistare <steven.sistare@oracle.com>

> ---
>   accel/kvm/kvm-all.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 9060599cd7..a3e2d11763 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -3479,7 +3479,7 @@ int kvm_device_access(int fd, int group, uint64_t attr,
>   
>   bool kvm_has_sync_mmu(void)
>   {
> -    return kvm_state->sync_mmu;
> +    return kvm_state && kvm_state->sync_mmu;
>   }
>   
>   int kvm_has_vcpu_events(void)