From: Martin Krastev krastevm@vmware.com

Much nicer now. Reviewed-by: Martin Krastev krastevm@vmware.com

Regards, Martin

On 8.02.23 г. 20:00 ч., Zack Rusin wrote:

From: Zack Rusin zackr@vmware.com

ttm_bo_init_reserved on failure puts the buffer object back which causes it to be deleted, but kfree was still being called on the same buffer in vmw_bo_create leading to a double free.

After the double free the vmw_gem_object_create_with_handle was setting the gem function objects before checking the return status of vmw_bo_create leading to null pointer access.

Fix the entire path by relaying on ttm_bo_init_reserved to delete the buffer objects on failure and making sure the return status is checked before setting the gem function objects on the buffer object.

Signed-off-by: Zack Rusin zackr@vmware.com Fixes: 8afa13a0583f ("drm/vmwgfx: Implement DRIVER_GEM") Cc: stable@vger.kernel.org # v5.17+

---

drivers/gpu/drm/vmwgfx/vmwgfx_bo.c | 4 +++- drivers/gpu/drm/vmwgfx/vmwgfx_gem.c | 4 ++-- 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c index 63486802c8fd..43ffa5c7acbd 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c @@ -431,13 +431,15 @@ int vmw_bo_create(struct vmw_private *vmw, return -ENOMEM; }

• /*

• * vmw_bo_init will delete the *p_bo object if it fails
  

• */
  

  ret = vmw_bo_init(vmw, *p_bo, params, vmw_bo_free); if (unlikely(ret != 0)) goto out_error;

return ret; out_error:

• kfree(*p_bo); *p_bo = NULL; return ret; }

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c index f042e22b8b59..51bd1f8c5cc4 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c @@ -127,11 +127,11 @@ int vmw_gem_object_create_with_handle(struct vmw_private *dev_priv, }; ret = vmw_bo_create(dev_priv, &params, p_vbo);

• (*p_vbo)->tbo.base.funcs = &vmw_gem_object_funcs; if (ret != 0) goto out_no_bo;

• (*p_vbo)->tbo.base.funcs = &vmw_gem_object_funcs;
• ret = drm_gem_handle_create(filp, &(*p_vbo)->tbo.base, handle); /* drop reference from allocate - handle holds it now */ drm_gem_object_put(&(*p_vbo)->tbo.base);