From: Christoph Hellwig <hch@lst.de>
To: Hongbo Yao <yaohongbo@huawei.com>
Cc: wangxiongfeng2@huawei.com, guohanjun@huawei.com,
huawei.libin@huawei.com, thunder.leizhen@huawei.com,
tanxiaojun@huawei.com, xiexiuqi@huawei.com,
yangyingliang@huawei.com, cj.chengjian@huawei.com,
wxf.wang@hisilicon.com, keith.busch@intel.com, axboe@fb.com,
hch@lst.de, sagi@grimberg.me, linux-nvme@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nvme: fix out of bounds access in nvme_cqe_pending
Date: Wed, 9 Jan 2019 19:39:20 +0100 [thread overview]
Message-ID: <20190109183920.GA22070@lst.de> (raw)
In-Reply-To: <1546827727-49635-1-git-send-email-yaohongbo@huawei.com>
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?
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index d668682..68375d4 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -908,9 +908,11 @@ static void nvme_complete_cqes(struct nvme_queue *nvmeq, u16 start, u16 end)
>
> static inline void nvme_update_cq_head(struct nvme_queue *nvmeq)
> {
> - if (++nvmeq->cq_head == nvmeq->q_depth) {
> + if (nvmeq->cq_head == (nvmeq->q_depth - 1)) {
> nvmeq->cq_head = 0;
> nvmeq->cq_phase = !nvmeq->cq_phase;
> + } else {
> + ++nvmeq->cq_head;
No need for the braces above, but otherwise this looks fine. I'll apply
it to nvme-4.21.
next prev parent reply other threads:[~2019-01-09 18:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 2:22 [PATCH] nvme: fix out of bounds access in nvme_cqe_pending Hongbo Yao
2019-01-09 18:39 ` Christoph Hellwig [this message]
2019-01-10 1:54 ` Yao HongBo
2019-01-10 14:50 ` Keith Busch
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