diff --git a/src/gallium/drivers/v3d/v3d_resource.c b/src/gallium/drivers/v3d/v3d_resource.c
index 1b806dfb089..8a11c5650e7 100644
--- a/src/gallium/drivers/v3d/v3d_resource.c
+++ b/src/gallium/drivers/v3d/v3d_resource.c
@@ -101,6 +101,10 @@ v3d_resource_bo_alloc(struct v3d_resource *rsc)
         struct pipe_screen *pscreen = prsc->screen;
         struct v3d_bo *bo;
 
+        /* never replace a mapped bo */
+        if (rsc->bo && rsc->bo->map)
+                return false;
+
         /* Buffers may be read using ldunifa, which prefetches the next
          * 4 bytes after a read. If the buffer's size is exactly a multiple
          * of a page size and the shader reads the last 4 bytes with ldunifa