From: Peng Hao <flyingpenghao@xxxxxxxxx> commit cf4a4493ff70874f8af26d75d4346c591c298e89 upstream. There is a check for vm->sbm.sb_states before, and it should check it here as well. Signed-off-by: Peng Hao <flyingpeng@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20211222011225.40573-1-flyingpeng@xxxxxxxxxxx Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Fixes: 5f1f79bbc9e2 ("virtio-mem: Paravirtualized memory hotplug") Cc: stable@xxxxxxxxxxxxxxx # v5.8+ Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/virtio/virtio_mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -577,7 +577,7 @@ static int virtio_mem_sbm_sb_states_prep return -ENOMEM; mutex_lock(&vm->hotplug_mutex); - if (new_bitmap) + if (vm->sbm.sb_states) memcpy(new_bitmap, vm->sbm.sb_states, old_pages * PAGE_SIZE); old_bitmap = vm->sbm.sb_states;
