On 29/07/19 10:58, Jack Wang wrote: > Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> 于2019年7月25日周四 下午3:29写道： >> >> From: Paolo Bonzini <pbonzini@xxxxxxxxxx> >> >> [ Upstream commit 88dddc11a8d6b09201b4db9d255b3394d9bc9e57 ] >> >> If a KVM guest is reset while running a nested guest, free_nested will >> disable the shadow VMCS execution control in the vmcs01. However, >> on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync >> the VMCS12 to the shadow VMCS which has since been freed. >> >> This causes a vmptrld of a NULL pointer on my machime, but Jan reports >> the host to hang altogether. Let's see how much this trivial patch fixes. >> >> Reported-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >> Cc: Liran Alon <liran.alon@xxxxxxxxxx> >> Cc: stable@xxxxxxxxxxxxxxx >> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > > Hi all, > > Do we need to backport the fix also to stable 4.14? It applies > cleanly and compiles fine. The reproducer required newer kernels that support KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE, so it would be hard to test it. However, the patch itself should be safe. Paolo
