From 5055a4379fe65d6f9ac74f204e448a8868a43569 Mon Sep 17 00:00:00 2001 From: Roy Shterman Date: Mon, 25 Dec 2017 14:18:30 +0200 Subject: [PATCH] nvme-fabrics: protect against module unload during create_ctrl NVMe transport driver module unload may (and usually does) trigger iteration over the active controllers and delete them all (sometimes under a mutex). However, a controller can be created concurrently with module unload which can lead to leakage of resources (most important char device node leakage) in case the controller creation occured after the unload delete and drain sequence. To protect against this, we take a module reference to guarantee that the nvme transport driver is not unloaded while creating a controller. Signed-off-by: Roy Shterman Signed-off-by: Sagi Grimberg Reviewed-by: Max Gurtovoy Signed-off-by: Christoph Hellwig --- drivers/nvme/host/fabrics.c | 17 +++++++++++++---- drivers/nvme/host/fabrics.h | 2 ++ drivers/nvme/host/fc.c | 1 + drivers/nvme/host/rdma.c | 1 + drivers/nvme/target/loop.c | 1 + 5 files changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c index 76b4fe6816a03..2f68befd31bf5 100644 --- a/drivers/nvme/host/fabrics.c +++ b/drivers/nvme/host/fabrics.c @@ -492,7 +492,7 @@ EXPORT_SYMBOL_GPL(nvmf_should_reconnect); */ int nvmf_register_transport(struct nvmf_transport_ops *ops) { - if (!ops->create_ctrl) + if (!ops->create_ctrl || !ops->module) return -EINVAL; down_write(&nvmf_transports_rwsem); @@ -868,32 +868,41 @@ nvmf_create_ctrl(struct device *dev, const char *buf, size_t count) goto out_unlock; } + if (!try_module_get(ops->module)) { + ret = -EBUSY; + goto out_unlock; + } + ret = nvmf_check_required_opts(opts, ops->required_opts); if (ret) - goto out_unlock; + goto out_module_put; ret = nvmf_check_allowed_opts(opts, NVMF_ALLOWED_OPTS | ops->allowed_opts | ops->required_opts); if (ret) - goto out_unlock; + goto out_module_put; ctrl = ops->create_ctrl(dev, opts); if (IS_ERR(ctrl)) { ret = PTR_ERR(ctrl); - goto out_unlock; + goto out_module_put; } if (strcmp(ctrl->subsys->subnqn, opts->subsysnqn)) { dev_warn(ctrl->device, "controller returned incorrect NQN: \"%s\".\n", ctrl->subsys->subnqn); + module_put(ops->module); up_read(&nvmf_transports_rwsem); nvme_delete_ctrl_sync(ctrl); return ERR_PTR(-EINVAL); } + module_put(ops->module); up_read(&nvmf_transports_rwsem); return ctrl; +out_module_put: + module_put(ops->module); out_unlock: up_read(&nvmf_transports_rwsem); out_free_opts: diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h index 9ba614953607e..25b19f722f5b2 100644 --- a/drivers/nvme/host/fabrics.h +++ b/drivers/nvme/host/fabrics.h @@ -108,6 +108,7 @@ struct nvmf_ctrl_options { * fabric implementation of NVMe fabrics. * @entry: Used by the fabrics library to add the new * registration entry to its linked-list internal tree. + * @module: Transport module reference * @name: Name of the NVMe fabric driver implementation. * @required_opts: sysfs command-line options that must be specified * when adding a new NVMe controller. @@ -126,6 +127,7 @@ struct nvmf_ctrl_options { */ struct nvmf_transport_ops { struct list_head entry; + struct module *module; const char *name; int required_opts; int allowed_opts; diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c index 0a8af4daef890..2a7a9a75105d7 100644 --- a/drivers/nvme/host/fc.c +++ b/drivers/nvme/host/fc.c @@ -3381,6 +3381,7 @@ nvme_fc_create_ctrl(struct device *dev, struct nvmf_ctrl_options *opts) static struct nvmf_transport_ops nvme_fc_transport = { .name = "fc", + .module = THIS_MODULE, .required_opts = NVMF_OPT_TRADDR | NVMF_OPT_HOST_TRADDR, .allowed_opts = NVMF_OPT_RECONNECT_DELAY | NVMF_OPT_CTRL_LOSS_TMO, .create_ctrl = nvme_fc_create_ctrl, diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c index 37af56596be6c..75d6956eb380c 100644 --- a/drivers/nvme/host/rdma.c +++ b/drivers/nvme/host/rdma.c @@ -2006,6 +2006,7 @@ out_free_ctrl: static struct nvmf_transport_ops nvme_rdma_transport = { .name = "rdma", + .module = THIS_MODULE, .required_opts = NVMF_OPT_TRADDR, .allowed_opts = NVMF_OPT_TRSVCID | NVMF_OPT_RECONNECT_DELAY | NVMF_OPT_HOST_TRADDR | NVMF_OPT_CTRL_LOSS_TMO, diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c index 1e21b286f2998..fdfcc961029f9 100644 --- a/drivers/nvme/target/loop.c +++ b/drivers/nvme/target/loop.c @@ -686,6 +686,7 @@ static struct nvmet_fabrics_ops nvme_loop_ops = { static struct nvmf_transport_ops nvme_loop_transport = { .name = "loop", + .module = THIS_MODULE, .create_ctrl = nvme_loop_create_ctrl, }; -- 2.39.5