Re: [lvc-project] [PATCH v2] drm/amd/pm: check return value of amdgpu_irq_add_id()

[Fedor Pchelkin]

On Wed, 02. Oct 16:01, Igor Artemiev wrote:
> amdgpu_irq_ad_id() may fail and the irq handlers will not be registered.
> This patch adds error code check.
> 
> Found by Linux Verification Center (linuxtesting.org) with static
> analysis tool SVACE.
> 
> Signed-off-by: Igor Artemiev <Igor.A.Artemiev@xxxxxxx>
> ---
> v2: Remove the cast to struct amdgpu_device as Christian König 
> <christian.koenig@xxxxxxx> suggested.
> 
>  .../drm/amd/pm/powerplay/hwmgr/smu_helper.c   | 19 ++++++++++++++++---
>  1 file changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu_helper.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu_helper.c
> index 79a566f3564a..50a3085c00aa 100644
> --- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu_helper.c
> +++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu_helper.c
> @@ -647,28 +647,41 @@ int smu9_register_irq_handlers(struct pp_hwmgr *hwmgr)
>  {
>  	struct amdgpu_irq_src *source =
>  		kzalloc(sizeof(struct amdgpu_irq_src), GFP_KERNEL);
> +	int ret;
>  
>  	if (!source)
>  		return -ENOMEM;
>  
>  	source->funcs = &smu9_irq_funcs;
>  
> -	amdgpu_irq_add_id((struct amdgpu_device *)(hwmgr->adev),
> +	ret = amdgpu_irq_add_id(hwmgr->adev,
>  			SOC15_IH_CLIENTID_THM,
>  			THM_9_0__SRCID__THM_DIG_THERM_L2H,
>  			source);
> -	amdgpu_irq_add_id((struct amdgpu_device *)(hwmgr->adev),
> +	if (ret)
> +		goto err;
> +
> +	ret = amdgpu_irq_add_id(hwmgr->adev,
>  			SOC15_IH_CLIENTID_THM,
>  			THM_9_0__SRCID__THM_DIG_THERM_H2L,
>  			source);
> +	if (ret)
> +		goto err;
>  
>  	/* Register CTF(GPIO_19) interrupt */
> -	amdgpu_irq_add_id((struct amdgpu_device *)(hwmgr->adev),
> +	ret = amdgpu_irq_add_id(hwmgr->adev,
>  			SOC15_IH_CLIENTID_ROM_SMUIO,
>  			SMUIO_9_0__SRCID__SMUIO_GPIO19,
>  			source);
> +	if (ret)
> +		goto err;
>  
>  	return 0;
> +
> +err:
> +	kfree(source);

Oh, the calltrace looks like:

hwmgr_sw_init()
  phm_register_irq_handlers()
    ->register_irq_handlers()
    smu9_register_irq_handlers()

And the return value of phm_register_irq_handlers() is not processed and
the error is not reported anywhere, so I guess there is a risk of
use-after-free: the source pointer may have been already registered by
some of amdgpu_irq_add_id() calls before the error occured.

The similar code exists in smu7_register_irq_handlers(), maybe should be
fixed as well.

Alex, is https://gitlab.freedesktop.org/agd5f/linux a public repo this
patch should go in? I'd suggest to drop the patch and ask Igor to do a
complete fix or, if dropping is not possible now, fix it by another patch.
For the latter one I can do this myself but it would be nice to refer to
the current patch via a git hash (it's probably not published yet in your
repo).

> +
> +	return ret;
>  }
>  
>  void *smu_atom_get_data_table(void *dev, uint32_t table, uint16_t *size,
> -- 
> 2.39.2