Re: [PATCH 2/3] drm/ttm/tests: Fix memory leak in ttm_tt_simple_create()

[Nirmoy Das]

On 10/14/2024 9:16 AM, Jinjie Ruan wrote:
> modprobe ttm_device_test and then rmmod ttm_device_test, the fllowing
> memory leaks occurs:
>
> The ttm->pages allocated in ttm_tt_init() is not freed after calling
> ttm_tt_simple_create(), which cause the memory leak:
>
> 	unreferenced object 0xffffff80caf27750 (size 8):
> 	  comm "kunit_try_catch", pid 2242, jiffies 4295055735
> 	  hex dump (first 8 bytes):
> 	    c0 1e 3d c3 fe ff ff ff                          ..=.....
> 	  backtrace (crc 3d11615a):
> 	    [<000000007f57312a>] kmemleak_alloc+0x34/0x40
> 	    [<000000008c6c4c7e>] __kmalloc_node_noprof+0x304/0x3e4
> 	    [<00000000679c1182>] __kvmalloc_node_noprof+0x1c/0x144
> 	    [<000000006aed0a3d>] ttm_tt_init+0x138/0x28c [ttm]
> 	    [<000000005c331998>] drm_gem_shmem_free+0x60/0x534 [drm_shmem_helper]
> 	    [<0000000022b4f375>] kunit_try_run_case+0x13c/0x3ac
> 	    [<00000000c525d725>] kunit_generic_run_threadfn_adapter+0x80/0xec
> 	    [<000000002db94a1f>] kthread+0x2e8/0x374
> 	    [<000000002c457ad7>] ret_from_fork+0x10/0x20
> 	......
>
> Fix it by calling ttm_tt_fini() in the exit function.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: e6f7c641fae3 ("drm/ttm/tests: Add tests for ttm_tt")
> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
Reviewed-by: Nirmoy Das <nirmoy.das@xxxxxxxxx>
> ---
>  drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c b/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
> index b91c13f46225..9ff216ec58ef 100644
> --- a/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
> +++ b/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
> @@ -54,6 +54,7 @@ static struct ttm_tt *ttm_tt_simple_create(struct ttm_buffer_object *bo, u32 pag
>  
>  static void ttm_tt_simple_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
>  {
> +	ttm_tt_fini(ttm);
>  	kfree(ttm);
>  }
>