From: "Walker, Benjamin" <benjamin.walker@intel.com>
To: "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: [bug report] nvme sends invalid command capsule over rdma transport for 5KiB write when target supports MSDBD > 1
Date: Mon, 24 May 2021 17:19:00 +0000 [thread overview]
Message-ID: <BYAPR11MB2824E1B94D81B837E474A7A6EF269@BYAPR11MB2824.namprd11.prod.outlook.com> (raw)
This bug was found using the iozone tool.
- Linux kernel initiator, SPDK target, RDMA (RoCEv2) transport
- iozone is performing a 5KiB write to a 512 byte block size nvme device
- The SPDK target has reported that it supports 4KiB of in-capsule data, MSDBD of 16 (number of SGL descriptors), and ICDOFF of 0.
- The Linux kernel sends an NVMe-oF capsule with a command that claims to have 5KiB of data in the command, but actually only has a single SGL element describing 4KiB of data in-capsule.
- The SPDK target correctly fails this I/O
This fails on at least 5.11 but worked prior to 5.4. A git bisect shows that this commit is responsible: 38e1800275d3af607e4df92ff49dc2cf442586a4
I believe the key is the use of MSDBD > 1 and in-capsule data support. This seems to trick the initiator into thinking it can do 5KiB in one command with two SGL elements, but then the initiator goes down the in-capsule data path and can only describe 4KiB that way.
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next reply other threads:[~2021-05-25 0:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-24 17:19 Walker, Benjamin [this message]
2021-05-26 9:12 ` [bug report] nvme sends invalid command capsule over rdma transport for 5KiB write when target supports MSDBD > 1 Sagi Grimberg
2021-05-26 14:10 ` Christoph Hellwig
2021-05-26 14:49 ` Max Gurtovoy
2021-05-26 16:00 ` Christoph Hellwig
2021-05-26 19:29 ` Walker, Benjamin
2021-05-26 21:57 ` Max Gurtovoy
2021-05-27 17:43 ` Walker, Benjamin
2021-05-27 17:48 ` Max Gurtovoy
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