Re: [PATCH 0/4] vsock/virtio: several fixes in the .probe() and .remove()

From: Stefan Hajnoczi
Date: Mon Jun 10 2019 - 09:14:13 EST

On Tue, May 28, 2019 at 12:56:19PM +0200, Stefano Garzarella wrote:
> During the review of "[PATCH] vsock/virtio: Initialize core virtio vsock
> before registering the driver", Stefan pointed out some possible issues
> in the .probe() and .remove() callbacks of the virtio-vsock driver.
> This series tries to solve these issues:
> - Patch 1 postpones the 'the_virtio_vsock' assignment at the end of the
> .probe() to avoid that some sockets queue works when the initialization
> is not finished.
> - Patches 2 and 3 stop workers before to call vdev->config->reset(vdev) to
> be sure that no one is accessing the device, and adds another flush at the
> end of the .remove() to avoid use after free.
> - Patch 4 free also used buffers in the virtqueues during the .remove().
> Stefano Garzarella (4):
> vsock/virtio: fix locking around 'the_virtio_vsock'
> vsock/virtio: stop workers during the .remove()
> vsock/virtio: fix flush of works during the .remove()
> vsock/virtio: free used buffers during the .remove()
> net/vmw_vsock/virtio_transport.c | 105 ++++++++++++++++++++++++++-----
> 1 file changed, 90 insertions(+), 15 deletions(-)

Looking forward to v2. I took a look at the discussion and I'll review
v2 from scratch. Just keep in mind that the mutex is used more for
mutual exclusion of the init/exit code than to protect the_virtio_vsock,
so we'll still need protection of init/exit code even with RCU.


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