6.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hannes Reinecke hare@kernel.org
[ Upstream commit 4082326807072b71496501b6a0c55ffe8d5092a5 ]
The namespace percpu counter protects pending I/O, and we can only safely diable the namespace once the counter drop to zero. Otherwise we end up with a crash when running blktests/nvme/058 (eg for loop transport):
[ 2352.930426] [ T53909] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI [ 2352.930431] [ T53909] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] [ 2352.930434] [ T53909] CPU: 3 UID: 0 PID: 53909 Comm: kworker/u16:5 Tainted: G W 6.13.0-rc6 #232 [ 2352.930438] [ T53909] Tainted: [W]=WARN [ 2352.930440] [ T53909] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 [ 2352.930443] [ T53909] Workqueue: nvmet-wq nvme_loop_execute_work [nvme_loop] [ 2352.930449] [ T53909] RIP: 0010:blkcg_set_ioprio+0x44/0x180
as the queue is already torn down when calling submit_bio();
So we need to init the percpu counter in nvmet_ns_enable(), and wait for it to drop to zero in nvmet_ns_disable() to avoid having I/O pending after the namespace has been disabled.
Fixes: 74d16965d7ac ("nvmet-loop: avoid using mutex in IO hotpath")
Signed-off-by: Hannes Reinecke hare@kernel.org Reviewed-by: Nilay Shroff nilay@linux.ibm.com Reviewed-by: Sagi Grimberg sagi@grimberg.me Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Chaitanya Kulkarni kch@nvidia.com Tested-by: Shin'ichiro Kawasaki shinichiro.kawasaki@wdc.com Signed-off-by: Keith Busch kbusch@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/target/core.c | 40 ++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 21 deletions(-)
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c index fde6c555af619..56e3c870ab4c3 100644 --- a/drivers/nvme/target/core.c +++ b/drivers/nvme/target/core.c @@ -606,6 +606,9 @@ int nvmet_ns_enable(struct nvmet_ns *ns) goto out_dev_put; }
+ if (percpu_ref_init(&ns->ref, nvmet_destroy_namespace, 0, GFP_KERNEL)) + goto out_pr_exit; + nvmet_ns_changed(subsys, ns->nsid); ns->enabled = true; xa_set_mark(&subsys->namespaces, ns->nsid, NVMET_NS_ENABLED); @@ -613,6 +616,9 @@ int nvmet_ns_enable(struct nvmet_ns *ns) out_unlock: mutex_unlock(&subsys->lock); return ret; +out_pr_exit: + if (ns->pr.enable) + nvmet_pr_exit_ns(ns); out_dev_put: list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) pci_dev_put(radix_tree_delete(&ctrl->p2p_ns_map, ns->nsid)); @@ -638,6 +644,19 @@ void nvmet_ns_disable(struct nvmet_ns *ns)
mutex_unlock(&subsys->lock);
+ /* + * Now that we removed the namespaces from the lookup list, we + * can kill the per_cpu ref and wait for any remaining references + * to be dropped, as well as a RCU grace period for anyone only + * using the namepace under rcu_read_lock(). Note that we can't + * use call_rcu here as we need to ensure the namespaces have + * been fully destroyed before unloading the module. + */ + percpu_ref_kill(&ns->ref); + synchronize_rcu(); + wait_for_completion(&ns->disable_done); + percpu_ref_exit(&ns->ref); + if (ns->pr.enable) nvmet_pr_exit_ns(ns);
@@ -660,22 +679,6 @@ void nvmet_ns_free(struct nvmet_ns *ns) if (ns->nsid == subsys->max_nsid) subsys->max_nsid = nvmet_max_nsid(subsys);
- mutex_unlock(&subsys->lock); - - /* - * Now that we removed the namespaces from the lookup list, we - * can kill the per_cpu ref and wait for any remaining references - * to be dropped, as well as a RCU grace period for anyone only - * using the namepace under rcu_read_lock(). Note that we can't - * use call_rcu here as we need to ensure the namespaces have - * been fully destroyed before unloading the module. - */ - percpu_ref_kill(&ns->ref); - synchronize_rcu(); - wait_for_completion(&ns->disable_done); - percpu_ref_exit(&ns->ref); - - mutex_lock(&subsys->lock); subsys->nr_namespaces--; mutex_unlock(&subsys->lock);
@@ -705,9 +708,6 @@ struct nvmet_ns *nvmet_ns_alloc(struct nvmet_subsys *subsys, u32 nsid) ns->nsid = nsid; ns->subsys = subsys;
- if (percpu_ref_init(&ns->ref, nvmet_destroy_namespace, 0, GFP_KERNEL)) - goto out_free; - if (ns->nsid > subsys->max_nsid) subsys->max_nsid = nsid;
@@ -730,8 +730,6 @@ struct nvmet_ns *nvmet_ns_alloc(struct nvmet_subsys *subsys, u32 nsid) return ns; out_exit: subsys->max_nsid = nvmet_max_nsid(subsys); - percpu_ref_exit(&ns->ref); -out_free: kfree(ns); out_unlock: mutex_unlock(&subsys->lock);