The indicated patch introduced a barrier in the sysfs_delete attribute for the controller that rejects the request if the controller isn't created. "Created" is defined as at least 1 call to nvme_start_ctrl().
This is problematic in error-injection testing. If an error occurs on the initial attempt to create an association and the controller enters reconnect(s) attempts, the admin cannot delete the controller until either there is a successful association created or ctrl_loss_tmo times out.
Where this issue is particularly hurtful is when the "admin" is the nvme-cli, it is performing a connection to a discovery controller, and it is initiated via auto-connect scripts. With the FC transport, if the first connection attempt fails, the controller enters a normal reconnect state but returns control to the cli thread that created the controller. In this scenario, the cli attempts to read the discovery log via ioctl, which fails, causing the cli to see it as an empty log and then proceeds to delete the discovery controller. The delete is rejected and the controller is left live. If the discovery controller reconnect then succeeds, there is no action to delete it, and it sits live doing nothing.
Cc: stable@vger.kernel.org # v5.7+ Fixes: ce1518139e69 ("nvme: Fix controller creation races with teardown flow") Signed-off-by: James Smart james.smart@broadcom.com CC: Israel Rukshin israelr@mellanox.com CC: Max Gurtovoy maxg@mellanox.com CC: Christoph Hellwig hch@lst.de CC: Keith Busch kbusch@kernel.org CC: Sagi Grimberg sagi@grimberg.me --- drivers/nvme/host/core.c | 5 ----- drivers/nvme/host/nvme.h | 1 - 2 files changed, 6 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 05aa568a60af..86abce864aa9 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3481,10 +3481,6 @@ static ssize_t nvme_sysfs_delete(struct device *dev, { struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
- /* Can't delete non-created controllers */ - if (!ctrl->created) - return -EBUSY; - if (device_remove_file_self(dev, attr)) nvme_delete_ctrl_sync(ctrl); return count; @@ -4355,7 +4351,6 @@ void nvme_start_ctrl(struct nvme_ctrl *ctrl) nvme_queue_scan(ctrl); nvme_start_queues(ctrl); } - ctrl->created = true; } EXPORT_SYMBOL_GPL(nvme_start_ctrl);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index c5c1bac797aa..45cf360fefbc 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -300,7 +300,6 @@ struct nvme_ctrl { struct nvme_command ka_cmd; struct work_struct fw_act_work; unsigned long events; - bool created;
#ifdef CONFIG_NVME_MULTIPATH /* asymmetric namespace access: */