netdev - Re: rtlwifi: Memory leak in rtl92c_set_fw

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Date:   Sat, 2 Nov 2019 01:54:26 +0100
From:   Stefan Wahren <wahrenst@....net>
To:     Pkshih <pkshih@...ltek.com>,
        Larry Finger <Larry.Finger@...inger.net>
Cc:     "colin.king@...onical.com" <colin.king@...onical.com>,
        "kvalo@...eaurora.org" <kvalo@...eaurora.org>,
        "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: rtlwifi: Memory leak in rtl92c_set_fw_rsvdpagepkt()


Am 01.11.19 um 02:18 schrieb Pkshih:
>
>> -----Original Message-----
>> From: Stefan Wahren [mailto:wahrenst@....net]
>> Sent: Thursday, October 31, 2019 9:57 PM
>> To: Pkshih; Larry Finger
>> Cc: colin.king@...onical.com; kvalo@...eaurora.org; linux-wireless@...r.kernel.org;
>> netdev@...r.kernel.org
>> Subject: rtlwifi: Memory leak in rtl92c_set_fw_rsvdpagepkt()
>>
>> Hi,
>>
>> i tested the EDIMAX EW-7612 on Raspberry Pi 3B+ with Linux 5.4-rc5
>> (multi_v7_defconfig + rtlwifi + kmemleak) and noticed a single memory
>> leak during probe:
>>
>> unreferenced object 0xec13ee40 (size 176):
>>   comm "kworker/u8:1", pid 36, jiffies 4294939321 (age 5580.790s)
>>   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:
>>     [<fc1bbb3e>] __netdev_alloc_skb+0x9c/0x164
>>     [<863dfa6e>] rtl92c_set_fw_rsvdpagepkt+0x254/0x340 [rtl8192c_common]
>>     [<9572be0d>] rtl92cu_set_hw_reg+0xf48/0xfa4 [rtl8192cu]
>>     [<116df4d8>] rtl_op_bss_info_changed+0x234/0x96c [rtlwifi]
>>     [<8933575f>] ieee80211_bss_info_change_notify+0xb8/0x264 [mac80211]
>>     [<d4061e86>] ieee80211_assoc_success+0x934/0x1798 [mac80211]
>>     [<e55adb56>] ieee80211_rx_mgmt_assoc_resp+0x174/0x314 [mac80211]
>>     [<5974629e>] ieee80211_sta_rx_queued_mgmt+0x3f4/0x7f0 [mac80211]
>>     [<d91091c6>] ieee80211_iface_work+0x208/0x318 [mac80211]
>>     [<ac5fcae4>] process_one_work+0x22c/0x564
>>     [<f5e6d3b6>] worker_thread+0x44/0x5d8
>>     [<82c7b073>] kthread+0x150/0x154
>>     [<b43e1b7d>] ret_from_fork+0x14/0x2c
>>     [<794dff30>] 0x0
>>
>> It looks like the allocated skd is never freed.
>>
>> Would be nice to get this fixed.
>>
> Hi,
>
> This is due to 8192cu doesn't implement usb_cmd_send_packet(). Could you help
> following patch?
>
> diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
> index 56cc3bc30860..f070f25bb735 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/hw.c
> @@ -1540,6 +1540,8 @@ static bool usb_cmd_send_packet(struct ieee80211_hw *hw, struct sk_buff *skb)
>     * This is maybe necessary:
>     * rtlpriv->cfg->ops->fill_tx_cmddesc(hw, buffer, 1, 1, skb);
>     */
> +       dev_kfree_skb(skb);
> +
>         return true;
>  }
>
> This patch just frees the skb to resolve memleak problem. Since 8192cu doesn't
> turn on fwctrl_lps that needs to download command packet to firmware, apply
> this patch isn't worse than before.

Yes, the patch fixes the memleak.

Thanks
Stefan

>
> ---
> PK
>