Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <0c8a4d70-3ef9-bc1c-51ad-9063fdfb43bc@acm.org>
Date:   Thu, 30 Jun 2022 11:42:53 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.10.0
Subject: Re: use-after-free in srpt_enable_tpg()
Content-Language: en-US
To:     Mike Christie <michael.christie@oracle.com>
Cc:     "lizhijian@fujitsu.com" <lizhijian@fujitsu.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Leon Romanovsky <leon@kernel.org>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "target-devel@vger.kernel.org" <target-devel@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <17649b9c-7e42-1625-8bc9-8ad333ab771c@fujitsu.com>
 <ed7e268e-94c5-38b1-286d-e2cb10412334@acm.org>
 <fbaca135-891c-7ff3-d7ac-bd79609849f5@oracle.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <fbaca135-891c-7ff3-d7ac-bd79609849f5@oracle.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 6/30/22 09:40, Mike Christie wrote:
> On 6/27/22 11:37 AM, Bart Van Assche wrote:
>> On 6/27/22 00:09, lizhijian@fujitsu.com wrote:
>>> So far, I doubt if the previous defect of configfs mentioned in
>>> 9b64f7d0b: "(RDMA/srpt: Postpone HCA removal until after configfs
>>> directory removal)" has got a better solution. if not, i have no a
>>> clear mechanism to avoid it yet.
>>>
>>> feedbacks are very welcome.
>> Mike, are you perhaps aware of any plans to add functions to the LIO core for removing tpg and wwn objects?
>>
> 
> I don't know any work being done in this area. I was only working
> on the refcounting/configfs parts for sessions in those configfs/sysfs
> patchsets. However, I think I hit similar issues with the session.
> I went around the world with solutions but didn't really like them
> so I never pushed the patches for inclusion.
> 
> What was the hang caused by 9b64f7d0bb0a?

Hi Mike,

I have not been able to find Honggang's bug report that led to the 
revert of that commit. I guess that the hang happened in the while-loop 
in srpt_release_sport() that was modified by commit 9b64f7d0bb0a.

Thanks,

Bart.