Re: [PATCH] phy: qcom-qusb2: Fix a memory leak on probe

From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Cc: Andy Gross <agross@kernel.org>,
	Kishon Vijay Abraham I <kishon@ti.com>,
	Vinod Koul <vkoul@kernel.org>,
	Vivek Gautam <vivek.gautam@codeaurora.org>,
	linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org
Subject: Re: [PATCH] phy: qcom-qusb2: Fix a memory leak on probe
Date: Wed, 22 Sep 2021 15:56:55 -0700	[thread overview]
Message-ID: <YUu0txXFw2fL3Fgq@ripper> (raw)
In-Reply-To: <20210922221613.2115038-1-vladimir.zapolskiy@linaro.org>

On Wed 22 Sep 15:16 PDT 2021, Vladimir Zapolskiy wrote:

> On success nvmem_cell_read() returns a pointer to a dynamically allocated
> buffer, and therefore it shall be freed after usage.
> 
> The issue is reported by kmemleak:
> 
>   # cat /sys/kernel/debug/kmemleak
>   unreferenced object 0xffff3b3803e4b280 (size 128):
>     comm "kworker/u16:1", pid 107, jiffies 4294892861 (age 94.120s)
>     hex dump (first 32 bytes):
>       00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>       00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>     backtrace:
>       [<000000007739afdc>] __kmalloc+0x27c/0x41c
>       [<0000000071c0fbf8>] nvmem_cell_read+0x40/0xe0
>       [<00000000e803ef1f>] qusb2_phy_init+0x258/0x5bc
>       [<00000000fc81fcfa>] phy_init+0x70/0x110
>       [<00000000e3d48a57>] dwc3_core_soft_reset+0x4c/0x234
>       [<0000000027d1dbd4>] dwc3_core_init+0x68/0x990
>       [<000000001965faf9>] dwc3_probe+0x4f4/0x730
>       [<000000002f7617ca>] platform_probe+0x74/0xf0
>       [<00000000a2576cac>] really_probe+0xc4/0x470
>       [<00000000bc77f2c5>] __driver_probe_device+0x11c/0x190
>       [<00000000130db71f>] driver_probe_device+0x48/0x110
>       [<0000000019f36c2b>] __device_attach_driver+0xa4/0x140
>       [<00000000e5812ff7>]  bus_for_each_drv+0x84/0xe0
>       [<00000000f4bac574>] __device_attach+0xe4/0x1c0
>       [<00000000d3beb631>] device_initial_probe+0x20/0x30
>       [<000000008019b9db>] bus_probe_device+0xa4/0xb0
> 
> Fixes: 0b56e9a7e835 ("phy: Group vendor specific phy drivers")
> Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
> ---
>  drivers/phy/qualcomm/phy-qcom-qusb2.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-qusb2.c b/drivers/phy/qualcomm/phy-qcom-qusb2.c
> index 3c1d3b71c825..061665ba8ef7 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qusb2.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qusb2.c
> @@ -589,6 +589,8 @@ static void qusb2_phy_set_tune2_param(struct qusb2_phy *qphy)
>  		qusb2_write_mask(qphy->base, cfg->regs[QUSB2PHY_PORT_TUNE2],
>  				 val[0] << HSTX_TRIM_SHIFT,
>  				 HSTX_TRIM_MASK);
> +
> +	kfree(val);

Nice catch, here's my:

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

That said, do you think we could replace the nvmem_cell_read() with a
call to nvmem_cell_read_u8() to avoid the need to clean it up instead?

Regards,
Bjorn

>  }
>  
>  static int qusb2_phy_set_mode(struct phy *phy,
> -- 
> 2.33.0
> 

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