diff --git a/src/gallium/drivers/llvmpipe/lp_flush.c b/src/gallium/drivers/llvmpipe/lp_flush.c
index c49836432a9..ee509010f37 100644
--- a/src/gallium/drivers/llvmpipe/lp_flush.c
+++ b/src/gallium/drivers/llvmpipe/lp_flush.c
@@ -57,7 +57,9 @@ llvmpipe_flush( struct pipe_context *pipe,
    /* ask the setup module to flush */
    lp_setup_flush(llvmpipe->setup, reason);
 
+   mtx_lock(&screen->rast_mutex);
    lp_rast_fence(screen->rast, (struct lp_fence **)fence);
+   mtx_unlock(&screen->rast_mutex);
    if (fence && (!*fence))
       *fence = (struct pipe_fence_handle *)lp_fence_create(0);
 
diff --git a/src/gallium/drivers/llvmpipe/lp_setup.c b/src/gallium/drivers/llvmpipe/lp_setup.c
index cf2317186ee..89519c96611 100644
--- a/src/gallium/drivers/llvmpipe/lp_setup.c
+++ b/src/gallium/drivers/llvmpipe/lp_setup.c
@@ -1714,7 +1714,9 @@ lp_setup_end_query(struct lp_setup_context *setup, struct llvmpipe_query *pq)
    }
    else {
       struct llvmpipe_screen *screen = llvmpipe_screen(setup->pipe->screen);
+      mtx_lock(&screen->rast_mutex);
       lp_rast_fence(screen->rast, &pq->fence);
+      mtx_unlock(&screen->rast_mutex);
    }
 
 fail: