From 16065fcdd19ddb9e093192914ac863884f308766 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 8 Feb 2019 15:04:09 +0100
Subject: [PATCH] drm/virtio: do NOT reuse resource ids
Bisected guest kernel changes crashing qemu. Landed at
"6c1cd97bda drm/virtio: fix resource id handling". Looked again, and
noticed we where not only leaking *some* ids, but *all* ids. The old
code never ever called virtio_gpu_resource_id_put().
So, commit 6c1cd97bda effectively makes the linux kernel starting
re-using IDs after releasing them, and apparently virglrenderer can't
deal with that. Oops.
This patch puts a temporary stopgap into place for the 5.0 release.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190208140409.15280-1-kraxel@redhat.com
---
drivers/gpu/drm/virtio/virtgpu_object.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index f39a183d59c2b..e7e946035027b 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -28,10 +28,21 @@
static int virtio_gpu_resource_id_get(struct virtio_gpu_device *vgdev,
uint32_t *resid)
{
+#if 0
int handle = ida_alloc(&vgdev->resource_ida, GFP_KERNEL);
if (handle < 0)
return handle;
+#else
+ static int handle;
+
+ /*
+ * FIXME: dirty hack to avoid re-using IDs, virglrenderer
+ * can't deal with that. Needs fixing in virglrenderer, also
+ * should figure a better way to handle that in the guest.
+ */
+ handle++;
+#endif
*resid = handle + 1;
return 0;
@@ -39,7 +50,9 @@ static int virtio_gpu_resource_id_get(struct virtio_gpu_device *vgdev,
static void virtio_gpu_resource_id_put(struct virtio_gpu_device *vgdev, uint32_t id)
{
+#if 0
ida_free(&vgdev->resource_ida, id - 1);
+#endif
}
static void virtio_gpu_ttm_bo_destroy(struct ttm_buffer_object *tbo)
--
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