Re: [PATCH] lightnvm: add a lock to prevent before the race condition on pblk remove

["Javier González" <javier@javigon.com>]

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> On 19 Mar 2019, at 15.24, Marcin Dziegielewski <marcin.dziegielewski@intel.com> wrote:
> 
> When we trigger nvm target remove during device hot unplug, we
> have a chance to hit general protection fault caused by use of
> nvm_dev which was freed from another (hot unplug) thread (in
> nvm_unregister function).
> 
> This patch introduce lock in nvme_ioctl_dev_remove function to
> prevent us before a situation like described above.
> 
> Signed-off-by: Marcin Dziegielewski <marcin.dziegielewski@intel.com>
> ---
> drivers/lightnvm/core.c | 2 ++
> 1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 5f82036..84f0b9a 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -1335,11 +1335,13 @@ static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
> 		return -EINVAL;
> 	}
> 
> +	down_read(&nvm_lock);
> 	list_for_each_entry(dev, &nvm_devices, devices) {
> 		ret = nvm_remove_tgt(dev, &remove);
> 		if (!ret)
> 			break;
> 	}
> +	up_read(&nvm_lock);
> 
> 	return ret;
> }
> --
> 1.8.3.1

Looks good to me.


Reviewed-by: Javier González <javier@javigon.com>


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