Message-ID: <2098bb01-1aad-cb38-8b0b-a43e4c40c013@linux.alibaba.com>
Date:   Mon, 10 Jan 2022 21:56:05 +0800
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Subject: Re: [PATCH net 1/3] net/smc: Resolve the race between link group
 access and termination
To:     Karsten Graul <kgraul@linux.ibm.com>, davem@davemloft.net,
        kuba@kernel.org
Cc:     linux-s390@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1641806784-93141-1-git-send-email-guwen@linux.alibaba.com>
 <1641806784-93141-2-git-send-email-guwen@linux.alibaba.com>
 <3525a4cd-1bc7-1008-910b-fb89597cc10a@linux.ibm.com>
From:   Wen Gu <guwen@linux.alibaba.com>
In-Reply-To: <3525a4cd-1bc7-1008-910b-fb89597cc10a@linux.ibm.com>
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On 2022/1/10 8:25 pm, Karsten Graul wrote:
> On 10/01/2022 10:26, Wen Gu wrote:
>> We encountered some crashes caused by the race between the access
>> and the termination of link groups.
>>

>> @@ -1120,8 +1122,22 @@ void smc_conn_free(struct smc_connection *conn)
>>   {
>>   	struct smc_link_group *lgr = conn->lgr;
>>   
>> -	if (!lgr)
>> +	if (!lgr || conn->freed)
>> +		/* The connection has never been registered in a
>> +		 * link group, or has already been freed.
>> +		 *
>> +		 * Check to ensure that the refcnt of link group
>> +		 * won't be put incorrectly.
> 
> I would delete the second sentence here, its obvious enough.
> 
>> +		 */
>>   		return;
>> +
>> +	conn->freed = 1;
>> +	if (!conn->alert_token_local)
>> +		/* The connection was registered in a link group
>> +		 * defore, but now it is unregistered from it.
> 
> 'before' ... But would maybe the following be more exact:
> 
> 'Connection already unregistered from link group.'
> 
> 
> We still review the patches...
> 

Thanks for your detailed and patient review. The comments will
be improved as you suggested.

Thanks,
Wen Gu