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Commit 3c0e3ab2 authored by Thomas Hellstrom's avatar Thomas Hellstrom Committed by Luis Henriques
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drm/vmwgfx: Fix up user_dmabuf refcounting 

commit 54c12bc3 upstream.

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.
Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: default avatarBrian Paul <brianp@vmware.com>
Reviewed-by: default avatarSinclair Yeh <syeh@vmware.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent c918c41d
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Showing with 39 additions and 17 deletions
drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
View file @ 3c0e3ab2
......@@ -610,7 +610,8 @@ 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);
......@@ -624,7 +625,8 @@ 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,
......
drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
View file @ 3c0e3ab2
......@@ -873,7 +873,8 @@ 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");
return -EINVAL;
......@@ -934,7 +935,8 @@ 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");
return -EINVAL;
......
drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c
View file @ 3c0e3ab2
......@@ -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;
......
drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
View file @ 3c0e3ab2
......@@ -355,7 +355,7 @@ 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;
}
......@@ -482,7 +482,8 @@ 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;
......@@ -516,6 +517,10 @@ 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:
......@@ -627,6 +632,7 @@ 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
......@@ -639,7 +645,8 @@ 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;
......@@ -647,6 +654,7 @@ 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",
......@@ -688,7 +696,8 @@ 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;
......@@ -717,7 +726,8 @@ 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;
......@@ -739,6 +749,9 @@ 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);
if (p_base)
*p_base = base;
else
ttm_base_object_unref(&base);
*out = &vmw_user_bo->dma;
......@@ -1000,7 +1013,7 @@ 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;
......@@ -1028,7 +1041,7 @@ 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;
......
drivers/gpu/drm/vmwgfx/vmwgfx_shader.c
View file @ 3c0e3ab2
......@@ -455,7 +455,7 @@ int vmw_shader_define_ioctl(struct drm_device *dev, void *data,
if (arg->buffer_handle != SVGA3D_INVALID_ID) {
ret = vmw_user_dmabuf_lookup(tfile, arg->buffer_handle,
&buffer);
&buffer, NULL);
if (unlikely(ret != 0)) {
DRM_ERROR("Could not find buffer for shader "
"creation.\n");
......
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
View file @ 3c0e3ab2
......@@ -43,6 +43,7 @@ struct vmw_user_surface {
struct vmw_surface srf;
uint32_t size;
struct drm_master *master;
struct ttm_base_object *backup_base;
};
/**
......@@ -652,6 +653,7 @@ 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);
}
......@@ -846,7 +848,8 @@ 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;
......@@ -1309,7 +1312,8 @@ 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);
} else if (req->drm_surface_flags &
drm_vmw_surface_flag_create_buffer)
ret = vmw_user_dmabuf_alloc(dev_priv, tfile,
......@@ -1317,7 +1321,8 @@ 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);
......
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