Message-ID: <bcb33716-5c14-38d4-8721-1585e9fb8461@huawei.com>
Date:   Sun, 29 Jan 2023 14:28:39 +0800
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Subject: Re: [PATCH v2] wifi: mac80211: fix memory leak in
 ieee80211_register_hw()
To:     Johannes Berg <johannes@sipsolutions.net>,
        <linux-wireless@vger.kernel.org>, <netdev@vger.kernel.org>,
        <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>
CC:     <sara.sharon@intel.com>, <luciano.coelho@intel.com>,
        <weiyongjun1@huawei.com>, <yuehaibing@huawei.com>
References: <20221202043838.2324539-1-shaozhengchao@huawei.com>
 <e33356c3b654db03030d371e38f02c6019e9c1a7.camel@sipsolutions.net>
From:   shaozhengchao <shaozhengchao@huawei.com>
In-Reply-To: <e33356c3b654db03030d371e38f02c6019e9c1a7.camel@sipsolutions.net>
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On 2023/1/18 17:45, Johannes Berg wrote:
> On Fri, 2022-12-02 at 12:38 +0800, Zhengchao Shao wrote:
>>
>> --- a/net/mac80211/main.c
>> +++ b/net/mac80211/main.c
>> @@ -1326,6 +1326,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
>>   					      hw->rate_control_algorithm);
>>   	rtnl_unlock();
>>   	if (result < 0) {
>> +		ieee80211_txq_teardown_flows(local);
>>   		wiphy_debug(local->hw.wiphy,
>>   			    "Failed to initialize rate control algorithm\n");
>>   		goto fail_rate;
>> @@ -1364,6 +1365,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
>>   
>>   		sband = kmemdup(sband, sizeof(*sband), GFP_KERNEL);
>>   		if (!sband) {
>> +			ieee80211_txq_teardown_flows(local);
>>   			result = -ENOMEM;
>>   			goto fail_rate;
>>   		}
> 
> I don't understand - we have a fail_rate label here where we free
> everything.
> 
> What if we get to fail_wiphy_register, don't we leak it in the same way?
> 
> johannes

Hi johannes:
	Thank you for your review. Sorry it took so long to reply. The
fail_rate label does not release the resources applied for in the
ieee80211_txq_setup_flows().  Or maybe I missed something?
	The fail_wiphy_register label will call
ieee80211_remove_interfaces()->ieee80211_txq_teardown_flows() to release
resources. So it is OK.

Zhengchao Shao