Re: Kernel OOPS while creating a NVMe Namespace

[Sagi Grimberg <sagi@grimberg.me>]

On 10/06/2024 22:15, Keith Busch wrote:
> On Mon, Jun 10, 2024 at 10:05:00PM +0300, Sagi Grimberg wrote:
>>
>> On 10/06/2024 21:53, Keith Busch wrote:
>>> On Mon, Jun 10, 2024 at 01:21:00PM +0530, Venkat Rao Bagalkote wrote:
>>>> Issue is introduced by the patch: be647e2c76b27f409cdd520f66c95be888b553a3.
>>> My mistake. The namespace remove list appears to be getting corrupted
>>> because I'm using the wrong APIs to replace a "list_move_tail". This is
>>> fixing the issue on my end:
>>>
>>> ---
>>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>>> index 7c9f91314d366..c667290de5133 100644
>>> --- a/drivers/nvme/host/core.c
>>> +++ b/drivers/nvme/host/core.c
>>> @@ -3959,9 +3959,10 @@ static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
>>>    	mutex_lock(&ctrl->namespaces_lock);
>>>    	list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
>>> -		if (ns->head->ns_id > nsid)
>>> -			list_splice_init_rcu(&ns->list, &rm_list,
>>> -					     synchronize_rcu);
>>> +		if (ns->head->ns_id > nsid) {
>>> +			list_del_rcu(&ns->list);
>>> +			list_add_tail_rcu(&ns->list, &rm_list);
>>> +		}
>>>    	}
>>>    	mutex_unlock(&ctrl->namespaces_lock);
>>>    	synchronize_srcu(&ctrl->srcu);
>>> --
>> Can we add a reproducer for this in blktests? I'm assuming that we can
>> easily trigger this
>> with adding/removing nvmet namespaces?
> I'm testing this with Namespace Manamgent commands, which nvmet doesn't
> support. You can recreate the issue by detaching the last namespace.
>

I think the same will happen in a test that creates two namespaces and 
then echo 0 > ns/enable.