commit 
963545357202 ("fuse: reduce allocation size for splice_write")
changed size of bufs array, so BUG_ON which checks the index of the array
shold also be fixed.
[SzM: turn BUG_ON into WARN_ON]
Fixes: 963545357202 ("fuse: reduce allocation size for splice_write")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
                struct pipe_buffer *ibuf;
                struct pipe_buffer *obuf;
 
-               BUG_ON(nbuf >= pipe->ring_size);
-               BUG_ON(tail == head);
+               if (WARN_ON(nbuf >= count || tail == head))
+                       goto out_free;
+
                ibuf = &pipe->bufs[tail & mask];
                obuf = &bufs[nbuf];