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Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20201022083850.1334880-1-pizhenwei@bytedance.com> Content-Language: en-US X-Originating-IP: [10.169.42.93] X-ClientProxiedBy: dggeme702-chm.china.huawei.com (10.1.199.98) To dggema772-chm.china.huawei.com (10.1.198.214) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201022_055507_482117_0C5E518E X-CRM114-Status: GOOD ( 18.96 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 2020/10/22 16:38, 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: > > 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. > > Handle data length, ignore zero bytes message, and try to recovery for > corrupted CQE case. > > Signed-off-by: zhenwei pi > --- > drivers/nvme/host/rdma.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c > index 9e378d0a0c01..9f5112040d43 100644 > --- a/drivers/nvme/host/rdma.c > +++ b/drivers/nvme/host/rdma.c > @@ -1767,6 +1767,17 @@ static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc) > return; > } > > + if (unlikely(!wc->byte_len)) { > + /* zero bytes message could be ignored */ > + return; > + } else if (unlikely(wc->byte_len < len)) { > + /* Corrupted completion, try to recovry */ > + dev_err(queue->ctrl->ctrl.device, > + "Unexpected nvme completion length(%d)\n", wc->byte_len); > + nvme_rdma_error_recovery(queue->ctrl); > + return; > + } !wc->byte_len and wc->byte_len < len may be the same type of anomaly. Why do different error handling? In which scenario zero bytes message received from target? fault inject test or normal test/run? > + > ib_dma_sync_single_for_cpu(ibdev, qe->dma, len, DMA_FROM_DEVICE); > /* > * AEN requests are special as they don't time out and can > _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme