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Date:   Fri, 29 Oct 2021 06:46:10 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     "Ziyang Xuan (William)" <william.xuanziyang@huawei.com>,
        davem@davemloft.net, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org
Subject: Re: [PATCH net] net: vlan: fix a UAF in vlan_dev_real_dev()
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On Fri, 29 Oct 2021 09:13:24 -0300 Jason Gunthorpe wrote:
> Jakub's path would be to test vlan_dev->reg_state != NETREG_REGISTERED
> in the work queue, but that feels pretty hacky to me as the main point
> of the UNREGISTERING state is to keep the object alive enough that
> those with outstanding gets can compelte their work and release the
> get. Leaving a wrecked object in UNREGISTERING is a bad design.

That or we should investigate if we could hold the ref for real_dev all
the way until vlan_dev_free().