Have nvmet_req_init() and req->execute() complete failed commands.

Description of the problem: nvmet_req_init() calls __nvmet_req_complete() internally upon failure, e.g., unsupported opcode, which calls the "queue_response" callback, this results in nvmet_pci_epf_queue_response() being called, which will call nvmet_pci_epf_complete_iod() if data_len is 0 or if dma_dir is different from DMA_TO_DEVICE. This results in a double completion as nvmet_pci_epf_exec_iod_work() also calls nvmet_pci_epf_complete_iod() when nvmet_req_init() fails.

Steps to reproduce: On the host send a command with an unsupported opcode with nvme-cli, For example the admin command "security receive" $ sudo nvme security-recv /dev/nvme0n1 -n1 -x4096

This triggers a double completion as nvmet_req_init() fails and nvmet_pci_epf_queue_response() is called, here iod->dma_dir is still in the default state of "DMA_NONE" as set by default in nvmet_pci_epf_alloc_iod(), so nvmet_pci_epf_complete_iod() is called. Because nvmet_req_init() failed nvmet_pci_epf_complete_iod() is also called in nvmet_pci_epf_exec_iod_work() leading to a double completion. This not only sends two completions to the host but also corrupts the state of the PCI NVMe target leading to kernel oops.

This patch lets nvmet_req_init() and req->execute() complete all failed commands, and removes the double completion case in nvmet_pci_epf_exec_iod_work() therefore fixing the edge cases where double completions occurred.

Signed-off-by: Rick Wertenbroek rick.wertenbroek@gmail.com Reviewed-by: Damien Le Moal dlemoal@kernel.org Fixes: 0faa0fe6f90e ("nvmet: New NVMe PCI endpoint function target driver") Cc: stable@vger.kernel.org --- drivers/nvme/target/pci-epf.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/target/pci-epf.c b/drivers/nvme/target/pci-epf.c index a4295a5b8d28..9cd470938463 100644 --- a/drivers/nvme/target/pci-epf.c +++ b/drivers/nvme/target/pci-epf.c @@ -1242,8 +1242,11 @@ static void nvmet_pci_epf_queue_response(struct nvmet_req *req)

iod->status = le16_to_cpu(req->cqe->status) >> 1;

- /* If we have no data to transfer, directly complete the command. */ - if (!iod->data_len || iod->dma_dir != DMA_TO_DEVICE) { + /* + * If the command failed or we have no data to transfer, complete + * the command immediately. + */ + if (iod->status || !iod->data_len || iod->dma_dir != DMA_TO_DEVICE) { nvmet_pci_epf_complete_iod(iod); return; } @@ -1604,8 +1607,13 @@ static void nvmet_pci_epf_exec_iod_work(struct work_struct *work) goto complete; }

+ /* + * If nvmet_req_init() fails (e.g., unsupported opcode) it will call + * __nvmet_req_complete() internally which will call + * nvmet_pci_epf_queue_response() and will complete the command directly. + */ if (!nvmet_req_init(req, &iod->sq->nvme_sq, &nvmet_pci_epf_fabrics_ops)) - goto complete; + return;

iod->data_len = nvmet_req_transfer_len(req); if (iod->data_len) { @@ -1643,10 +1651,11 @@ static void nvmet_pci_epf_exec_iod_work(struct work_struct *work)

wait_for_completion(&iod->done);

- if (iod->status == NVME_SC_SUCCESS) { - WARN_ON_ONCE(!iod->data_len || iod->dma_dir != DMA_TO_DEVICE); - nvmet_pci_epf_transfer_iod_data(iod); - } + if (iod->status != NVME_SC_SUCCESS) + return; + + WARN_ON_ONCE(!iod->data_len || iod->dma_dir != DMA_TO_DEVICE); + nvmet_pci_epf_transfer_iod_data(iod);

complete: nvmet_pci_epf_complete_iod(iod);