From: "Tan, Jianfeng" <jianfeng.tan@intel.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>,
"Chen, Junjie J" <junjie.j.chen@intel.com>,
"mtetsuyah@gmail.com" <mtetsuyah@gmail.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] net/vhost: fix segfault when creating vdev dynamically
Date: Tue, 27 Mar 2018 22:01:21 +0800 [thread overview]
Message-ID: <45023f15-9ddd-ec64-8e06-bef74c2ca533@intel.com> (raw)
In-Reply-To: <c10fca40-a071-8678-4d25-88a468fe1eb8@redhat.com>
On 3/27/2018 7:28 PM, Maxime Coquelin wrote:
>
>
> On 03/27/2018 11:42 AM, Tan, Jianfeng wrote:
>>
>>
>> On 3/27/2018 5:24 PM, Chen, Junjie J wrote:
>>>>>> On 3/28/2018 12:05 AM, Junjie Chen wrote:
>>>>>>> when creating vdev dynamically, vhost pmd driver start directly
>>>>>>> without checking TX/RX queues ready or not, and thus cause
>>>>>>> segmentation fault when vhost library accessing queues. This patch
>>>>>>> add flag to check whether queues setup or not, and add driver start
>>>>>>> call into dev_start to allow user start it after setting up queue.
>>>>>> The issue is clear now. But this patch just puts the situation
>>>>>> before below
>>>> fix:
>>>>>> "it doesn't create the actual datagram socket until you call
>>>>>> .dev_start()."
>>>>> No, if the queue exist, the datagram socket still get created in
>>>>> vhost_create
>>>> API, since the vhost_driver_register still exist in vhost_create.
>>>>
>>>> The queue can never be created, as it's still not probed.
>>> I think we need to separate this into two cases:
>>> Statically create vdev, the datagram recreate logical is still
>>> there since queues are exist already, this patch doesn't change
>>> anything.
>>> Dynamic create vdev, as you pointed out, queue can never be
>>> created, while this should be not valid since In normal process of
>>> creating vdev dynamically, we always need to config queues. Correct
>>> me if I'm wrong.
>>
>> My point is, either vdev is created statically or dynamically, when
>> probe(), queues are not setup yet definitely, then *the unix socket
>> will not be created* until we set up the queues and do dev_start().
>> If the unix socket is not created, then VM cannot connect to it.
>
> FYI, I think I reproduced such an issue with the vdev statically created
> in the past, while doing some experiments. I didn't went further into
> the analysis at that time, but it looks like the issue Junjie is trying
> to address with this patch for dynamically created vdev.
Yes, I have noticed that this issue mostly happens at dynamic case. Just
try to suggest a proper way to fix. Please check if my suggestion in
another email makes sense.
Thanks,
Jianfeng
>
> Cheers,
> Maxime
next prev parent reply other threads:[~2018-03-27 14:01 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-27 16:05 Junjie Chen
2018-03-27 8:56 ` Tan, Jianfeng
2018-03-27 9:02 ` Chen, Junjie J
2018-03-27 9:10 ` Tan, Jianfeng
2018-03-27 9:24 ` Chen, Junjie J
2018-03-27 9:42 ` Tan, Jianfeng
2018-03-27 10:18 ` Chen, Junjie J
2018-03-27 13:54 ` Tan, Jianfeng
2018-03-27 11:28 ` Maxime Coquelin
2018-03-27 14:01 ` Tan, Jianfeng [this message]
2018-03-29 12:35 ` Maxime Coquelin
2018-03-29 15:35 ` [dpdk-dev] [PATCH v2] " Junjie Chen
2018-03-29 13:16 ` Maxime Coquelin
2018-03-30 6:58 ` [dpdk-dev] [PATCH v3] " Junjie Chen
2018-03-30 7:32 ` Yang, Zhiyong
2018-03-30 7:36 ` Maxime Coquelin
2018-03-30 7:35 ` Maxime Coquelin
2018-03-30 7:43 ` Maxime Coquelin
2018-04-09 12:37 ` Jens Freimann
2018-04-10 8:11 ` Chen, Junjie J
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