[PATCH 1/2] accel/ivpu: Fix deadlock in ivpu_ms_cleanup()

[Lizhi Hou]

On 3/28/25 01:23, Jacek Lawrynowicz wrote:
>
> On 3/27/2025 6:38 PM, Lizhi Hou wrote:
>> On 3/26/25 01:06, Jacek Lawrynowicz wrote:
>>> Hi,
>>>
>>> On 3/25/2025 9:50 PM, Lizhi Hou wrote:
>>>> On 3/25/25 04:43, Maciej Falkowski wrote:
>>>>> From: Jacek Lawrynowicz <jacek.lawrynowicz at linux.intel.com>
>>>>>
>>>>> Fix deadlock in ivpu_ms_cleanup() by preventing runtime resume after
>>>>> file_priv->ms_lock is acquired.
>>>>>
>>>>> During a failure in runtime resume, a cold boot is executed, which
>>>>> calls ivpu_ms_cleanup_all(). This function calls ivpu_ms_cleanup()
>>>>> that acquires file_priv->ms_lock and causes the deadlock.
>>>>>
>>>>> Fixes: cdfad4db7756 ("accel/ivpu: Add NPU profiling support")
>>>>> Cc: <stable at vger.kernel.org> # v6.11+
>>>>> Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz at linux.intel.com>
>>>>> Signed-off-by: Maciej Falkowski <maciej.falkowski at linux.intel.com>
>>>>> ---
>>>>>     drivers/accel/ivpu/ivpu_ms.c | 6 ++++++
>>>>>     1 file changed, 6 insertions(+)
>>>>>
>>>>> diff --git a/drivers/accel/ivpu/ivpu_ms.c b/drivers/accel/ivpu/ivpu_ms.c
>>>>> index ffe7b10f8a76..eb485cf15ad6 100644
>>>>> --- a/drivers/accel/ivpu/ivpu_ms.c
>>>>> +++ b/drivers/accel/ivpu/ivpu_ms.c
>>>>> @@ -4,6 +4,7 @@
>>>>>      */
>>>>>       #include <drm/drm_file.h>
>>>>> +#include <linux/pm_runtime.h>
>>>>>       #include "ivpu_drv.h"
>>>>>     #include "ivpu_gem.h"
>>>>> @@ -281,6 +282,9 @@ int ivpu_ms_get_info_ioctl(struct drm_device *dev, void *data, struct drm_file *
>>>>>     void ivpu_ms_cleanup(struct ivpu_file_priv *file_priv)
>>>>>     {
>>>>>         struct ivpu_ms_instance *ms, *tmp;
>>>>> +    struct ivpu_device *vdev = file_priv->vdev;
>>>>> +
>>>>> +    pm_runtime_get_sync(vdev->drm.dev);
>>>> Could get_sync() be failed here? Maybe it is better to add warning for failure?
>>> Yes, this could fail but we already have detailed warnings in runtime resume callback (ivpu_pm_runtime_resume_cb()).
>> Will the deadlock still happens if this function fails?
> No. The deadlock was caused by runtime resume in free_instance().
> pm_runtime_get_sync() will always bump PM usage counter, so there will be no resume regardless if it fails or not.
Reviewed-by: Lizhi Hou <lizhi.hou at amd.com>
>>>>>           mutex_lock(&file_priv->ms_lock);
>>>>>     @@ -293,6 +297,8 @@ void ivpu_ms_cleanup(struct ivpu_file_priv *file_priv)
>>>>>             free_instance(file_priv, ms);
>>>>>           mutex_unlock(&file_priv->ms_lock);
>>>>> +
>>>>> +    pm_runtime_put_autosuspend(vdev->drm.dev);
>>>>>     }
>>>>>       void ivpu_ms_cleanup_all(struct ivpu_device *vdev)
>>> Regards,
>>> Jacek
>>>