From: Max Gurtovoy <mgurtovoy@nvidia.com>
To: zhenwei pi <pizhenwei@bytedance.com>, <kbusch@kernel.org>,
<axboe@fb.com>, <hch@lst.de>, <sagi@grimberg.me>
Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
lengchao@huawei.com
Subject: Re: [PATCH v3] nvme-rdma: handle nvme completion data length
Date: Wed, 28 Oct 2020 18:58:08 +0200 [thread overview]
Message-ID: <86fa6106-b969-4bb9-95ee-c1101a61ff03@nvidia.com> (raw)
In-Reply-To: <20201025115124.1430678-1-pizhenwei@bytedance.com>
On 10/25/2020 1:51 PM, zhenwei pi wrote:
> Hit a kernel warning:
> refcount_t: underflow; use-after-free.
> WARNING: CPU: 0 PID: 0 at lib/refcount.c:28
>
> RIP: 0010:refcount_warn_saturate+0xd9/0xe0
> Call Trace:
> <IRQ>
> nvme_rdma_recv_done+0xf3/0x280 [nvme_rdma]
> __ib_process_cq+0x76/0x150 [ib_core]
> ...
>
> The reason is that a zero bytes message received from target, and the
> host side continues to process without length checking, then the
> previous CQE is processed twice.
>
> Do sanity check on received data length, try to recovery for corrupted
> CQE case.
>
> Because zero bytes message in not defined in spec, using zero bytes
> message to detect dead connections on transport layer is not
> standard, currently still treat it as illegal.
>
> Thanks to Chao Leng & Sagi for suggestions.
>
> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
> ---
> drivers/nvme/host/rdma.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
Seems strange that the targets sends zero byte packets.
Can you specify which target is this and the scenario ?
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prev parent reply other threads:[~2020-10-28 16:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-25 11:51 [PATCH v3] nvme-rdma: handle nvme completion data length zhenwei pi
2020-10-26 7:40 ` Sagi Grimberg
2020-10-27 9:07 ` Christoph Hellwig
2020-10-28 16:58 ` Max Gurtovoy [this message]
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