If user space calls unreference on a user_dmabuf it will typically
kill the struct ttm_base_object member which is responsible for the
user-space visibility. However the dmabuf part may still be alive and
refcounted. In some situations, like for shared guest-backed surface
referencing/opening, the driver may try to reference the
struct ttm_base_object member again, causing an immediate kernel warning
and a later kernel NULL pointer dereference.
Fix this by always maintaining a reference on the struct
ttm_base_object member, in situations where it might subsequently be
referenced.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Reviewed-by: Brian Paul <brianp@xxxxxxxxxx>
Reviewed-by: Sinclair Yeh <syeh@xxxxxxxxxx>
---
drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 6 ++++--
drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c | 6 ++++--
drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c | 2 +-
drivers/gpu/drm/vmwgfx/vmwgfx_resource.c | 29 +++++++++++++++++++++--------
drivers/gpu/drm/vmwgfx/vmwgfx_shader.c | 2 +-
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 11 ++++++++---
6 files changed, 39 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 8f40692..b60b41f 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -631,7 +631,8 @@ extern int vmw_user_dmabuf_alloc(struct vmw_private *dev_priv,
uint32_t size,
bool shareable,
uint32_t *handle,
- struct vmw_dma_buffer **p_dma_buf);
+ struct vmw_dma_buffer **p_dma_buf,
+ struct ttm_base_object **p_base);
extern int vmw_user_dmabuf_reference(struct ttm_object_file *tfile,
struct vmw_dma_buffer *dma_buf,
uint32_t *handle);
@@ -645,7 +646,8 @@ extern uint32_t vmw_dmabuf_validate_node(struct ttm_buffer_object *bo,
uint32_t cur_validate_node);
extern void vmw_dmabuf_validate_clear(struct ttm_buffer_object *bo);
extern int vmw_user_dmabuf_lookup(struct ttm_object_file *tfile,
- uint32_t id, struct vmw_dma_buffer **out);
+ uint32_t id, struct vmw_dma_buffer **out,
+ struct ttm_base_object **base);
extern int vmw_stream_claim_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);
extern int vmw_stream_unref_ioctl(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index b565654..5da5de0 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -1236,7 +1236,8 @@ static int vmw_translate_mob_ptr(struct vmw_private *dev_priv,
struct vmw_relocation *reloc;
int ret;
- ret = vmw_user_dmabuf_lookup(sw_context->fp->tfile, handle, &vmw_bo);
+ ret = vmw_user_dmabuf_lookup(sw_context->fp->tfile, handle, &vmw_bo,
+ NULL);
if (unlikely(ret != 0)) {
DRM_ERROR("Could not find or use MOB buffer.\n");
ret = -EINVAL;
@@ -1296,7 +1297,8 @@ static int vmw_translate_guest_ptr(struct vmw_private *dev_priv,
struct vmw_relocation *reloc;
int ret;
- ret = vmw_user_dmabuf_lookup(sw_context->fp->tfile, handle, &vmw_bo);
+ ret = vmw_user_dmabuf_lookup(sw_context->fp->tfile, handle, &vmw_bo,
+ NULL);
if (unlikely(ret != 0)) {
DRM_ERROR("Could not find or use GMR region.\n");
ret = -EINVAL;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c
index 76069f0..222c9c2 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c
@@ -484,7 +484,7 @@ int vmw_overlay_ioctl(struct drm_device *dev, void *data,
goto out_unlock;
}
- ret = vmw_user_dmabuf_lookup(tfile, arg->handle, &buf);
+ ret = vmw_user_dmabuf_lookup(tfile, arg->handle, &buf, NULL);
if (ret)
goto out_unlock;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
index c1912f8..e57667c 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
@@ -354,7 +354,7 @@ int vmw_user_lookup_handle(struct vmw_private *dev_priv,
}
*out_surf = NULL;
- ret = vmw_user_dmabuf_lookup(tfile, handle, out_buf);
+ ret = vmw_user_dmabuf_lookup(tfile, handle, out_buf, NULL);
return ret;
}
@@ -481,7 +481,8 @@ int vmw_user_dmabuf_alloc(struct vmw_private *dev_priv,
uint32_t size,
bool shareable,
uint32_t *handle,
- struct vmw_dma_buffer **p_dma_buf)
+ struct vmw_dma_buffer **p_dma_buf,
+ struct ttm_base_object **p_base)
{
struct vmw_user_dma_buffer *user_bo;
struct ttm_buffer_object *tmp;
@@ -515,6 +516,10 @@ int vmw_user_dmabuf_alloc(struct vmw_private *dev_priv,
}
*p_dma_buf = &user_bo->dma;
+ if (p_base) {
+ *p_base = &user_bo->prime.base;
+ kref_get(&(*p_base)->refcount);
+ }
*handle = user_bo->prime.base.hash.key;
out_no_base_object:
@@ -631,6 +636,7 @@ int vmw_user_dmabuf_synccpu_ioctl(struct drm_device *dev, void *data,
struct vmw_dma_buffer *dma_buf;
struct vmw_user_dma_buffer *user_bo;
struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
+ struct ttm_base_object *buffer_base;
int ret;
if ((arg->flags & (drm_vmw_synccpu_read | drm_vmw_synccpu_write)) == 0
@@ -643,7 +649,8 @@ int vmw_user_dmabuf_synccpu_ioctl(struct drm_device *dev, void *data,
switch (arg->op) {
case drm_vmw_synccpu_grab:
- ret = vmw_user_dmabuf_lookup(tfile, arg->handle, &dma_buf);
+ ret = vmw_user_dmabuf_lookup(tfile, arg->handle, &dma_buf,
+ &buffer_base);
if (unlikely(ret != 0))
return ret;
@@ -651,6 +658,7 @@ int vmw_user_dmabuf_synccpu_ioctl(struct drm_device *dev, void *data,
dma);
ret = vmw_user_dmabuf_synccpu_grab(user_bo, tfile, arg->flags);
vmw_dmabuf_unreference(&dma_buf);
+ ttm_base_object_unref(&buffer_base);
if (unlikely(ret != 0 && ret != -ERESTARTSYS &&
ret != -EBUSY)) {
DRM_ERROR("Failed synccpu grab on handle 0x%08x.\n",
@@ -692,7 +700,8 @@ int vmw_dmabuf_alloc_ioctl(struct drm_device *dev, void *data,
return ret;
ret = vmw_user_dmabuf_alloc(dev_priv, vmw_fpriv(file_priv)->tfile,
- req->size, false, &handle, &dma_buf);
+ req->size, false, &handle, &dma_buf,
+ NULL);
if (unlikely(ret != 0))
goto out_no_dmabuf;
@@ -721,7 +730,8 @@ int vmw_dmabuf_unref_ioctl(struct drm_device *dev, void *data,
}
int vmw_user_dmabuf_lookup(struct ttm_object_file *tfile,
- uint32_t handle, struct vmw_dma_buffer **out)
+ uint32_t handle, struct vmw_dma_buffer **out,
+ struct ttm_base_object **p_base)
{
struct vmw_user_dma_buffer *vmw_user_bo;
struct ttm_base_object *base;
@@ -743,7 +753,10 @@ int vmw_user_dmabuf_lookup(struct ttm_object_file *tfile,
vmw_user_bo = container_of(base, struct vmw_user_dma_buffer,
prime.base);
(void)ttm_bo_reference(&vmw_user_bo->dma.base);
- ttm_base_object_unref(&base);
+ if (p_base)
+ *p_base = base;
+ else
+ ttm_base_object_unref(&base);
*out = &vmw_user_bo->dma;
return 0;
@@ -1004,7 +1017,7 @@ int vmw_dumb_create(struct drm_file *file_priv,
ret = vmw_user_dmabuf_alloc(dev_priv, vmw_fpriv(file_priv)->tfile,
args->size, false, &args->handle,
- &dma_buf);
+ &dma_buf, NULL);
if (unlikely(ret != 0))
goto out_no_dmabuf;
@@ -1032,7 +1045,7 @@ int vmw_dumb_map_offset(struct drm_file *file_priv,
struct vmw_dma_buffer *out_buf;
int ret;
- ret = vmw_user_dmabuf_lookup(tfile, handle, &out_buf);
+ ret = vmw_user_dmabuf_lookup(tfile, handle, &out_buf, NULL);
if (ret != 0)
return -EINVAL;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c
index bba1ee3..fd47547 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_shader.c
@@ -855,7 +855,7 @@ static int vmw_shader_define(struct drm_device *dev, struct drm_file *file_priv,
if (buffer_handle != SVGA3D_INVALID_ID) {
ret = vmw_user_dmabuf_lookup(tfile, buffer_handle,
- &buffer);
+ &buffer, NULL);
if (unlikely(ret != 0)) {
DRM_ERROR("Could not find buffer for shader "
"creation.\n");
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index 3361769..64b5040 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -46,6 +46,7 @@ struct vmw_user_surface {
struct vmw_surface srf;
uint32_t size;
struct drm_master *master;
+ struct ttm_base_object *backup_base;
};
/**
@@ -656,6 +657,7 @@ static void vmw_user_surface_base_release(struct ttm_base_object **p_base)
struct vmw_resource *res = &user_srf->srf.res;
*p_base = NULL;
+ ttm_base_object_unref(&user_srf->backup_base);
vmw_resource_unreference(&res);
}
@@ -851,7 +853,8 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
res->backup_size,
true,
&backup_handle,
- &res->backup);
+ &res->backup,
+ &user_srf->backup_base);
if (unlikely(ret != 0)) {
vmw_resource_unreference(&res);
goto out_unlock;
@@ -1321,7 +1324,8 @@ int vmw_gb_surface_define_ioctl(struct drm_device *dev, void *data,
if (req->buffer_handle != SVGA3D_INVALID_ID) {
ret = vmw_user_dmabuf_lookup(tfile, req->buffer_handle,
- &res->backup);
+ &res->backup,
+ &user_srf->backup_base);
if (ret == 0 && res->backup->base.num_pages * PAGE_SIZE <
res->backup_size) {
DRM_ERROR("Surface backup buffer is too small.\n");
@@ -1335,7 +1339,8 @@ int vmw_gb_surface_define_ioctl(struct drm_device *dev, void *data,
req->drm_surface_flags &
drm_vmw_surface_flag_shareable,
&backup_handle,
- &res->backup);
+ &res->backup,
+ &user_srf->backup_base);
if (unlikely(ret != 0)) {
vmw_resource_unreference(&res);
--
2.1.0
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