Subject: Re: [PATCH][V2] brcmfmac: fix leak of mypkt on error return path
To:     Colin King <colin.king@canonical.com>,
        Franky Lin <franky.lin@broadcom.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Chi-Hsien Lin <chi-hsien.lin@cypress.com>,
        Wright Feng <wright.feng@cypress.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S . Miller" <davem@davemloft.net>,
        linux-wireless@vger.kernel.org,
        brcm80211-dev-list.pdl@broadcom.com,
        brcm80211-dev-list@cypress.com, netdev@vger.kernel.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20190409114333.24342-1-colin.king@canonical.com>
From:   Arend Van Spriel <arend.vanspriel@broadcom.com>
Message-ID: <e0d984a7-6a6d-b902-6f75-26ee6f530efe@broadcom.com>
Date:   Tue, 9 Apr 2019 13:50:38 +0200
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On 4/9/2019 1:43 PM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently if the call to brcmf_sdiod_set_backplane_window fails then
> then error return path leaks mypkt. Fix this by returning by a new
> error path labelled 'out' that calls brcmu_pkt_buf_free_skb to free
> mypkt.  Also remove redundant check on err before calling
> brcmf_sdiod_skbuff_write.
> 
> Addresses-Coverity: ("Resource Leak")
> Fixes: a7c3aa1509e2 ("brcmfmac: Remove brcmf_sdiod_addrprep()")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> 
> V2: Remove  redundant check on err before calling
> brcmf_sdiod_skbuff_write, kudos to Dan Carpenter and Arend Van Spriel
> for spotting this.
> 
> ---
>   drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c | 8 +++-----
>   1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c
> index ec129864cc9c..60aede5abb4d 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/bcmsdh.c
> @@ -628,15 +628,13 @@ int brcmf_sdiod_send_buf(struct brcmf_sdio_dev *sdiodev, u8 *buf, uint nbytes)
>   
>   	err = brcmf_sdiod_set_backplane_window(sdiodev, addr);
>   	if (err)
> -		return err;
> +		goto out;
>   
>   	addr &= SBSDIO_SB_OFT_ADDR_MASK;
>   	addr |= SBSDIO_SB_ACCESS_2_4B_FLAG;
>   
> -	if (!err)
> -		err = brcmf_sdiod_skbuff_write(sdiodev, sdiodev->func2, addr,
> -					       mypkt);
> -
> +	err = brcmf_sdiod_skbuff_write(sdiodev, sdiodev->func2, addr, mypkt);
> +out:

I am fine with it, but my suggestion was a bit different:

	err = brcmf_sdiod_set_backplane_window(sdiodev, addr);
	if (!err) {
		addr &= SBSDIO_SB_OFT_ADDR_MASK;
		addr |= SBSDIO_SB_ACCESS_2_4B_FLAG;
		err = brcmf_sdiod_skbuff_write(sdiodev, sdiodev->func2,
					       addr, mypkt);
	}

>   	brcmu_pkt_buf_free_skb(mypkt);
>   
>   	return err;
>