From mboxrd@z Thu Jan  1 00:00:00 1970
From: bvanassche@acm.org (Bart Van Assche)
Date: Thu, 20 Sep 2018 10:31:29 -0700
Subject: Kernel v4.19-rc4 KASAN complaint
In-Reply-To: <20180920170145.GA31127@localhost.localdomain>
References: <6892a170-0dcf-9498-19c2-50e1ae89f4ef@acm.org>
 <20180920170145.GA31127@localhost.localdomain>
Message-ID: <1537464689.224533.10.camel@acm.org>

On Thu, 2018-09-20@11:01 -0600, Keith Busch wrote:
> On Tue, Sep 18, 2018@02:16:48PM -0700, Bart Van Assche wrote:
> > Hello,
> > 
> > If I run the nvmeof-mp tests from https://github.com/bvanassche/blktests
> > against kernel v4.19-rc4 then a KASAN complaint appears. This complaint does
> > not appear when I run these tests against kernel v4.18. Could this be a
> > regression?
> 
> Not sure if the following is what you're hitting since it wouldn't be a
> regression. It looks like removing a namespace path and clearing it as
> the current path is in the wrong order, such that the very next IO
> may reference the namespace being deleted.
> 
> ---
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 893f1fcc17cd..a01b6743d62b 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -3143,8 +3143,8 @@ static void nvme_ns_remove(struct nvme_ns *ns)
>  	}
>  
>  	mutex_lock(&ns->ctrl->subsys->lock);
> -	nvme_mpath_clear_current_path(ns);
>  	list_del_rcu(&ns->siblings);
> +	nvme_mpath_clear_current_path(ns);
>  	mutex_unlock(&ns->ctrl->subsys->lock);
>  
>  	down_write(&ns->ctrl->namespaces_rwsem);

That patch makes the KASAN complaint disappear on my test setup.

Thanks!

Bart.