diff --git a/block/bsg.c b/block/bsg.c
index d214e92..b9a5361 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -655,6 +655,9 @@
 
 	dprintk("%s: write %Zd bytes\n", bd->name, count);
 
+	if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
+		return -EINVAL;
+
 	bsg_set_block(bd, file);
 
 	bytes_written = 0;