Re: [Intel-wired-lan] [PATCH] ice: Fix some null pointer dereference issues in ice_ptp.c

From: Przemek Kitszel <przemyslaw.kitszel@intel.com>
To: Kunwu Chan <chentao@kylinos.cn>, <jesse.brandeburg@intel.com>,
	<anthony.l.nguyen@intel.com>, <davem@davemloft.net>,
	<edumazet@google.com>, <kuba@kernel.org>, <pabeni@redhat.com>,
	<richardcochran@gmail.com>, <jacob.e.keller@intel.com>,
	<karol.kolacinski@intel.com>
Cc: netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
	linux-kernel@vger.kernel.org, michal.michalik@intel.com,
	Kunwu Chan <kunwu.chan@hotmail.com>
Subject: Re: [Intel-wired-lan] [PATCH] ice: Fix some null pointer dereference issues in ice_ptp.c
Date: Mon, 11 Dec 2023 08:15:53 +0100	[thread overview]
Message-ID: <447d130a-e1ac-02f6-e168-b04bfa9c6004@intel.com> (raw)
In-Reply-To: <20231211062649.247148-1-chentao@kylinos.cn>

On 12/11/23 07:26, Kunwu Chan wrote:
> devm_kasprintf() returns a pointer to dynamically allocated memory
> which can be NULL upon failure.
> 
> Fixes: d938a8cca88a ("ice: Auxbus devices & driver for E822 TS")
> Cc: Kunwu Chan <kunwu.chan@hotmail.com>
> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>

I would suggest adding "iwl-net" as a target here

> ---
>   drivers/net/ethernet/intel/ice/ice_ptp.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
> index 1eddcbe89b0c..59794ce4f243 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.c
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
> @@ -2668,6 +2668,8 @@ static int ice_ptp_register_auxbus_driver(struct ice_pf *pf)
>   	name = devm_kasprintf(dev, GFP_KERNEL, "ptp_aux_dev_%u_%u_clk%u",
>   			      pf->pdev->bus->number, PCI_SLOT(pf->pdev->devfn),
>   			      ice_get_ptp_src_clock_index(&pf->hw));
> +	if (!name)
> +		return -ENOMEM;
>   
>   	aux_driver->name = name;
>   	aux_driver->shutdown = ice_ptp_auxbus_shutdown;
> @@ -2929,6 +2931,10 @@ static int ice_ptp_create_auxbus_device(struct ice_pf *pf)
>   	name = devm_kasprintf(dev, GFP_KERNEL, "ptp_aux_dev_%u_%u_clk%u",
>   			      pf->pdev->bus->number, PCI_SLOT(pf->pdev->devfn),
>   			      ice_get_ptp_src_clock_index(&pf->hw));
> +	if (!name) {
> +		dev_err(dev, "Failed to allocate memory\n");

Kuba @ [1]:
no warnings on allocation failures, there will be a splat for GFP_KERNEL
(checkpatch should catch this)

[1] https://lore.kernel.org/netdev/20231206195304.6226771d@kernel.org/T/

so just "return -ENOMEM" would be sufficient

> +		return -ENOMEM;
> +	}
>   
>   	aux_dev->name = name;
>   	aux_dev->id = id;

I didn't checked but having same code in two places raises questions.
Are you overwriting old name here, or our code is just self similar?
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