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Subject: Re: [PATCH v2] nvme: avoid race in shutdown namespace removal
To:     Christoph Hellwig <hch@infradead.org>,
        Daniel Wagner <dwagner@suse.de>
Cc:     linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        Keith Busch <kbusch@kernel.org>
References: <20210902092002.67614-1-dwagner@suse.de>
 <YTXKwOvCtJOHnhpu@infradead.org>
From:   Hannes Reinecke <hare@suse.de>
Message-ID: <d63a15af-63a7-3fa0-1559-4518dee3a99a@suse.de>
Date:   Mon, 6 Sep 2021 10:40:05 +0200
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On 9/6/21 10:01 AM, Christoph Hellwig wrote:
> On Thu, Sep 02, 2021 at 11:20:02AM +0200, Daniel Wagner wrote:
>> When we remove the siblings entry, we update ns->head->list, hence we
>> can't separate the removal and test for being empty. They have to be
>> in the same critical section to avoid a race.
>>
>> To avoid breaking the refcounting imbalance again, add a list empty
>> check to nvme_find_ns_head.
> 
> Hannes, can you look over this and run your tests on it?
> 
I'm at it.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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