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Date:   Thu, 27 Feb 2020 12:04:23 -0800 (PST)
Message-Id: <20200227.120423.2054408641031093845.davem@davemloft.net>
To:     sgarzare@redhat.com
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Subject: Re: [PATCH net] vsock: fix potential deadlock in
 transport->release()
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20200226105818.36055-1-sgarzare@redhat.com>
References: <20200226105818.36055-1-sgarzare@redhat.com>
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From: Stefano Garzarella <sgarzare@redhat.com>
Date: Wed, 26 Feb 2020 11:58:18 +0100

> Some transports (hyperv, virtio) acquire the sock lock during the
> .release() callback.
> 
> In the vsock_stream_connect() we call vsock_assign_transport(); if
> the socket was previously assigned to another transport, the
> vsk->transport->release() is called, but the sock lock is already
> held in the vsock_stream_connect(), causing a deadlock reported by
> syzbot:
 ...
> To avoid this issue, this patch remove the lock acquiring in the
> .release() callback of hyperv and virtio transports, and it holds
> the lock when we call vsk->transport->release() in the vsock core.
> 
> Reported-by: syzbot+731710996d79d0d58fbc@syzkaller.appspotmail.com
> Fixes: 408624af4c89 ("vsock: use local transport when it is loaded")
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

Applied, thank you.