Re: [PATCH] intel_th: avoid double free in error flow

[Alexander Shishkin <alexander.shishkin@linux.intel.com>]

Wen Yang <wenyang@linux.alibaba.com> writes:

> There is a possible double free issue in intel_th_subdevice_alloc:
>
> 651         err = intel_th_device_add_resources(thdev, res, subdev->nres);
> 652         if (err) {
> 653                 put_device(&thdev->dev);
> 654                 goto fail_put_device;     ---> freed
> 655         }
> ...
> 687 fail_put_device:
> 688         put_device(&thdev->dev);          ---> double freed
> 689
>
> This patch fix it by removing the unnecessary put_device().

Unnecessary is a too generous term here.

> Fixes: a753bfcfdb1f ("intel_th: Make the switch allocate its subdevices")
> Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-kernel@vger.kernel.org

Cc: stable@ is missing.

> ---
>  drivers/hwtracing/intel_th/core.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
> index d5c1821..98d195c 100644
> --- a/drivers/hwtracing/intel_th/core.c
> +++ b/drivers/hwtracing/intel_th/core.c
> @@ -649,10 +649,8 @@ static inline void intel_th_request_hub_module_flush(struct intel_th *th)
>  	}
>  
>  	err = intel_th_device_add_resources(thdev, res, subdev->nres);
> -	if (err) {
> -		put_device(&thdev->dev);
> +	if (err)
>  		goto fail_put_device;
> -	}

What about the second instance of the same problem a few lines lower?

Thanks,
--
Alex