On Thu, Dec 6, 2012 at 4:20 PM, Tim Gardner <tim.gardner@xxxxxxxxxxxxx> wrote:
> Memory for _manager is allocated using kzalloc() but the result is not checked.
>
> Free _manager on error lest memory become orphaned.
>
> I was led to scrutinize ttm_page_alloc_init() from a smatch warning:
>
> drivers/gpu/drm/ttm/ttm_page_alloc.c:799 ttm_page_alloc_init() error: potential null dereference '_manager'. (kzalloc returns null)
>
> Cc: David Airlie <airlied@xxxxxxxx>
> Cc: Dave Airlie <airlied@xxxxxxxxxx>
> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
> Cc: Zhao Yakui <yakui.zhao@xxxxxxxxx>
> Cc: David Howells <dhowells@xxxxxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx # 3.5+
> Signed-off-by: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>
> ---
>
> This patch applies to stable 3.5 and newer.
>
> drivers/gpu/drm/ttm/ttm_page_alloc.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
> index bd2a3b4..2c73d0a 100644
> --- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
> @@ -798,6 +798,10 @@ int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
> pr_info("Initializing pool allocator\n");
>
> _manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
> + if (!_manager) {
> + pr_err("ttm: Could not allocate _manager.\n");
> + return -ENOMEM;
> + }
This is fine,
>
> ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc");
>
> @@ -817,6 +821,7 @@ int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
> &glob->kobj, "pool");
> if (unlikely(ret != 0)) {
> kobject_put(&_manager->kobj);
> + kfree(_manager);
> _manager = NULL;
I don;t think this is, since the kobject_put shuold free it.
Dave.
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