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drm/vmwgfx: Fix possible usage of an uninitialized variable

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vmw_user_bo_lookup can fail to lookup user buffers, especially because
the buffer handles come from the userspace. The return value has
to be checked before the buffers are put back.

This was spotted by Dan's Smatch statick checker:
    drivers/gpu/drm/vmwgfx/vmwgfx_bo.c:574 vmw_user_bo_synccpu_release()
	error: uninitialized symbol 'vmw_bo'.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 8afa13a058 ("drm/vmwgfx: Implement DRIVER_GEM")
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211215200224.3693345-1-zack@kde.org
This commit is contained in:
Zack Rusin
2021-12-15 15:02:24 -05:00
parent 11343099d5
commit 60c9ecd705
1 changed files with 5 additions and 3 deletions
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8
drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
View File

@@ -568,10 +568,12 @@ static int vmw_user_bo_synccpu_release(struct drm_file *filp,
struct vmw_buffer_object *vmw_bo;
int ret = vmw_user_bo_lookup(filp, handle, &vmw_bo);
if (!(flags & drm_vmw_synccpu_allow_cs)) {
atomic_dec(&vmw_bo->cpu_writers);
if (!ret) {
if (!(flags & drm_vmw_synccpu_allow_cs)) {
atomic_dec(&vmw_bo->cpu_writers);
}
ttm_bo_put(&vmw_bo->base);
}
ttm_bo_put(&vmw_bo->base);
return ret;
}