Re: [PATCH v2] vfio: fix potential deadlock on vfio group lock

From: Jason Gunthorpe
Date: Fri Jan 13 2023 - 10:00:40 EST


On Thu, Jan 12, 2023 at 04:51:36PM -0500, Matthew Rosato wrote:

> Yep, thanks. I will surround this bit of code with
>
> mutex_lock(&device->dev_set->lock);
> ..
> mutex_unlock(&device->dev_set->lock);

Don't do it like that, copy the kvm out of the struct device to the
stack and NULL it. Then do the put without holding any locks.

Jason