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From: Wen Yang <wenyang@linux.alibaba.com>
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	stable@vger.kernel.org
Subject: Re: [GIT PULL 1/3] intel_th: Fix a double put_device() in error path
Date: Wed, 20 Nov 2019 21:36:46 +0800	[thread overview]
Message-ID: <2e648871-b7f7-c77e-6a22-3c26ad90633b@linux.alibaba.com> (raw)
In-Reply-To: <20191120130806.44028-2-alexander.shishkin@linux.intel.com>


On 2019/11/20 9:08 下午, Alexander Shishkin wrote:
> Commit a753bfcfdb1f ("intel_th: Make the switch allocate its subdevices")
> factored out intel_th_subdevice_alloc() from intel_th_populate(), but got
> the error path wrong, resulting in two instances of a double put_device()
> on a freshly initialized, but not 'added' device.
>
> Fix this by only doing one put_device() in the error path.
>
> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Fixes: a753bfcfdb1f ("intel_th: Make the switch allocate its subdevices")
> Reported-by: Wen Yang <wenyang@linux.alibaba.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: stable@vger.kernel.org # v4.14+
> ---
>   drivers/hwtracing/intel_th/core.c | 8 ++------
>   1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
> index d5c1821b31c6..0dfd97bbde9e 100644
> --- a/drivers/hwtracing/intel_th/core.c
> +++ b/drivers/hwtracing/intel_th/core.c
> @@ -649,10 +649,8 @@ intel_th_subdevice_alloc(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;
> -	}
>   
>   	if (subdev->type == INTEL_TH_OUTPUT) {
>   		if (subdev->mknode)
> @@ -667,10 +665,8 @@ intel_th_subdevice_alloc(struct intel_th *th,
>   	}
>   
>   	err = device_add(&thdev->dev);
> -	if (err) {
> -		put_device(&thdev->dev);
> +	if (err)
>   		goto fail_free_res;
> -	}
>   
>   	/* need switch driver to be loaded to enumerate the rest */
>   	if (subdev->type == INTEL_TH_SWITCH && !req) {
device_add() has increased the reference count,

so when it returns an error, an additional call to put_device()

is needed here to reduce the reference count.

--

Regards,

Wen



  reply	other threads:[~2019-11-20 13:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-20 13:08 [GIT PULL 0/3] intel_th: Updates for v5.5 Alexander Shishkin
2019-11-20 13:08 ` [GIT PULL 1/3] intel_th: Fix a double put_device() in error path Alexander Shishkin
2019-11-20 13:36   ` Wen Yang [this message]
2019-11-20 13:44     ` Alexander Shishkin
2019-11-20 13:08 ` [GIT PULL 2/3] intel_th: pci: Add Ice Lake CPU support Alexander Shishkin
2019-11-20 13:08 ` [GIT PULL 3/3] intel_th: pci: Add Tiger " Alexander Shishkin

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