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Message-ID: <675f7ef8-4c59-cfb4-1c46-39c3e7ea27db@huawei.com>
Date:   Thu, 27 Jan 2022 09:24:03 +0800
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Subject: Re: "blk-mq: fix tag_get wait task can't be awakened" causes hangs
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To:     Jens Axboe <axboe@kernel.dk>,
        "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        <linux-block@vger.kernel.org>
CC:     <john.garry@huawei.com>, <ming.lei@redhat.com>,
        <martin.petersen@oracle.com>, <hare@suse.de>,
        <akpm@linux-foundation.org>, <bvanassche@acm.org>,
        <linux-kernel@vger.kernel.org>
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 <723815a5-f716-499a-acce-15028a629f3a@kernel.dk>
From:   QiuLaibin <qiulaibin@huawei.com>
In-Reply-To: <723815a5-f716-499a-acce-15028a629f3a@kernel.dk>
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Hi

On 2022/1/26 21:38, Jens Axboe wrote:
> On 1/24/22 9:08 PM, QiuLaibin wrote:
>> Hi Alex
>>
>> 1、Please help to import this structure:
>>
>> blk_mq_tags <= request_queue->blk_mq_hw_ctx->blk_mq_tags
>>
>> If there is no kernel dump, help to see the value of
>>
>> cat /sys/block/sda/mq/0/nr_tags
>>                  __ <= Change it to the problem device
>>
>> And how many block devices in total by lsblk.
>>
>> 2、Please describe in detail how to reproduce the issue,
>>
>> And what type of USB device?
>>
>> 3、Please help to try the attachment patch and see if it can be reproduced.
> 
> Any progress on this? I strongly suspect that any QD=1 setup would
> trivially show the issue, based on the reports.
Yes, QD = 1 from Alex Xu's must-see environment. I'm trying to build a 
must-see locally, and I will submit the repaired patch as soon as possible.

> 

BR
Laibin