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Date:   Thu, 10 Jan 2019 07:50:08 -0700
From:   Keith Busch <keith.busch@intel.com>
To:     Yao HongBo <yaohongbo@huawei.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        "wangxiongfeng2@huawei.com" <wangxiongfeng2@huawei.com>,
        "guohanjun@huawei.com" <guohanjun@huawei.com>,
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        "tanxiaojun@huawei.com" <tanxiaojun@huawei.com>,
        "xiexiuqi@huawei.com" <xiexiuqi@huawei.com>,
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        "sagi@grimberg.me" <sagi@grimberg.me>,
        "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] nvme: fix out of bounds access in nvme_cqe_pending
Message-ID: <20190110145008.GA21095@localhost.localdomain>
References: <1546827727-49635-1-git-send-email-yaohongbo@huawei.com>
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On Wed, Jan 09, 2019 at 05:54:59PM -0800, Yao HongBo wrote:
> On 1/10/2019 2:39 AM, Christoph Hellwig wrote:
> > On Mon, Jan 07, 2019 at 10:22:07AM +0800, Hongbo Yao wrote:
> >> There is an out of bounds array access in nvme_cqe_peding().
> >>
> >> When enable irq_thread for nvme interrupt, there is racing between the
> >> nvmeq->cq_head updating and reading.
> > 
> > Just curious: why did you enable this option?  Do you have a workload
> > where it matters?
> 
> Yes, there were a lot of hard interrupts reported when reading the nvme disk,
> the OS can not schedule and result in the soft lockup.so i enabled the irq_thread.

That seems a little unusual. We should be able to handle as many
interrupts as an nvme drive can send.