linux-kernel - Re: [PATCH V2] nvme: fix nvme_remove going to uninterruptible sleep for ever

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Date:   Tue, 30 May 2017 13:18:55 +0300
From:   Sagi Grimberg <sagi@...mberg.me>
To:     Rakesh Pandit <rakesh@...era.com>, linux-nvme@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Cc:     Jens Axboe <axboe@...com>, Keith Busch <keith.busch@...el.com>,
        Christoph Hellwig <hch@....de>,
        Andy Lutomirski <luto@...nel.org>
Subject: Re: [PATCH V2] nvme: fix nvme_remove going to uninterruptible sleep
 for ever

>  	/*
> +	 * Avoid configuration and syncing commands if controller is already
> +	 * being removed and queues have been killed.
> +	 */
> +	if (ctrl->state == NVME_CTRL_DELETING || ctrl->state == NVME_CTRL_DEAD)
> +		return;
> +

Hey Rakesh, Christoph,

Given that the issue is for sync command submission during controller
removal, I'm wandering if we should perhaps move this check to
__nvme_submit_sync_cmd?

AFAICT user-space can just as easily trigger set_features in the same
condition which will trigger the hang couldn't it?