virtio/virtio_mem: handle a possible NULL as a memcpy parameter

There is a check for vm->sbm.sb_states before, and it should check it here as well. Signed-off-by: Peng Hao <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Michael S. Tsirkin <[email protected]> Fixes: 5f1f79b ("virtio-mem: Paravirtualized memory hotplug") Cc: [email protected] # v5.8+
sm00th · Jan 14, 2022 · cf4a449 · cf4a449
1 parent 2b68224
commit cf4a449
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
@@ -593,7 +593,7 @@ static int virtio_mem_sbm_sb_states_prepare_next_mb(struct virtio_mem *vm)
 		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;