netdev - Re: [PATCH v2] ath11k: mhi: fix potential memory leak in ath11k_mhi

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Message-ID: <bbc9d5c1-6b05-4e8a-3141-ffdb23e586be@quicinc.com>
Date:   Tue, 31 May 2022 14:51:25 -0700
From:   Jeff Johnson <quic_jjohnson@...cinc.com>
To:     Jianglei Nie <niejianglei2021@....com>, <kvalo@...nel.org>,
        <davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
        <pabeni@...hat.com>
CC:     <ath11k@...ts.infradead.org>, <linux-wireless@...r.kernel.org>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] ath11k: mhi: fix potential memory leak in
 ath11k_mhi_register()

On 5/30/2022 1:06 AM, Jianglei Nie wrote:
> mhi_alloc_controller() allocates a memory space for mhi_ctrl. When some
> errors occur, mhi_ctrl should be freed by mhi_free_controller() and set
> ab_pci->mhi_ctrl = NULL because ab_pci->mhi_ctrl has a dangling pointer
> to the freed memory. But when ath11k_mhi_read_addr_from_dt() fails, the
> function returns without calling mhi_free_controller(), which will lead
> to a memory leak.
> 
> We can fix it by calling mhi_free_controller() when
> ath11k_mhi_read_addr_from_dt() fails and set ab_pci->mhi_ctrl = NULL in
> all of the places where we call mhi_free_controller().
> 
> Signed-off-by: Jianglei Nie <niejianglei2021@....com>
> ---
>   drivers/net/wireless/ath/ath11k/mhi.c | 17 ++++++++++-------
>   1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c
> index fc3524e83e52..fc1bbf91c58e 100644
> --- a/drivers/net/wireless/ath/ath11k/mhi.c
> +++ b/drivers/net/wireless/ath/ath11k/mhi.c
> @@ -367,8 +367,7 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci)
>   	ret = ath11k_mhi_get_msi(ab_pci);
>   	if (ret) {
>   		ath11k_err(ab, "failed to get msi for mhi\n");
> -		mhi_free_controller(mhi_ctrl);
> -		return ret;
> +		goto free_controller;
>   	}
>   
>   	if (!test_bit(ATH11K_PCI_FLAG_MULTI_MSI_VECTORS, &ab_pci->flags))
> @@ -377,7 +376,7 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci)
>   	if (test_bit(ATH11K_FLAG_FIXED_MEM_RGN, &ab->dev_flags)) {
>   		ret = ath11k_mhi_read_addr_from_dt(mhi_ctrl);
>   		if (ret < 0)
> -			return ret;
> +			goto free_controller;
>   	} else {
>   		mhi_ctrl->iova_start = 0;
>   		mhi_ctrl->iova_stop = 0xFFFFFFFF;
> @@ -405,18 +404,22 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci)
>   	default:
>   		ath11k_err(ab, "failed assign mhi_config for unknown hw rev %d\n",
>   			   ab->hw_rev);
> -		mhi_free_controller(mhi_ctrl);
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto free_controller;
>   	}
>   
>   	ret = mhi_register_controller(mhi_ctrl, ath11k_mhi_config);
>   	if (ret) {
>   		ath11k_err(ab, "failed to register to mhi bus, err = %d\n", ret);
> -		mhi_free_controller(mhi_ctrl);
> -		return ret;
> +		goto free_controller;
>   	}
>   
>   	return 0;
> +
> +free_controller:
> +	mhi_free_controller(mhi_ctrl);
> +	ab_pci->mhi_ctrl = NULL;
> +	return ret;
>   }
>   
>   void ath11k_mhi_unregister(struct ath11k_pci *ab_pci)

LGTM, thanks

Reviewed-by: Jeff Johnson <quic_jjohnson@...cinc.com>