From: Ido Schimmel <idosch@nvidia.com>
To: Xiang Mei <xmei5@asu.edu>
Cc: Jakub Kicinski <kuba@kernel.org>,
Jiayuan Chen <jiayuan.chen@linux.dev>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@linux.dev>,
Jesper Dangaard Brouer <hawk@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
John Fastabend <john.fastabend@gmail.com>,
Stanislav Fomichev <sdf@fomichev.me>,
Alexei Starovoitov <ast@kernel.org>,
Jussi Maki <joamaki@gmail.com>, Paolo Abeni <pabeni@redhat.com>,
Weiming Shi <bestswngs@gmail.com>,
Ido Schimmel <idosch@idosch.org>, David Ahern <dsahern@gmail.com>
Subject: Re: [PATCH net] net, bpf: check master for NULL in xdp_master_redirect()
Date: Tue, 23 Jun 2026 09:52:18 +0300 [thread overview]
Message-ID: <20260623065218.GA378121@shredder> (raw)
In-Reply-To: <CAPpSM+Q4O704OaUAXqKpL6ffvudTfqzzLzLExziUExgvxQWmxw@mail.gmail.com>
On Mon, Jun 22, 2026 at 04:34:06PM -0700, Xiang Mei wrote:
> On Mon, Jun 22, 2026 at 3:58 PM Jakub Kicinski <kuba@kernel.org> wrote:
> > Can you double-confirm that this triggers on current HEAD
> > of linux/master ? I thought commit 2674d603a9e6 ("vrf: Fix a potential
> > NPD when removing a port from a VRF") was supposed to prevent all the
> > torn master fetches. Adding VRF folks to CC.
>
> Yes.
>
> We have triggered the crash on 56abdaebbf0da304b860bed1f2b5a85f5a6a16a0,
> which is the latest for net.git, and 2674d603a9e6 was applied. We can
> still trigger the crash:
2674d603a9e6 was only for VRF ports, so it doesn't help with this case
(bond port). Also, the problem that 2674d603a9e6 fixed is a bit
different. We had a NULL check after netdev_master_upper_dev_get_rcu(),
but the issue was that this master device was not necessarily a VRF
master.
Looking at __bond_release_one(), assuming that
netdev_master_upper_dev_get_rcu() returned a master device, I believe it
must be a bond because you have a synchronize_rcu() after
bond_upper_dev_unlink().
prev parent reply other threads:[~2026-06-23 6:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-20 20:15 [PATCH net] net, bpf: check master for NULL in xdp_master_redirect() Xiang Mei
2026-06-22 1:21 ` Jiayuan Chen
2026-06-22 1:28 ` Xiang Mei
2026-06-22 22:58 ` Jakub Kicinski
2026-06-22 23:34 ` Xiang Mei
2026-06-23 6:52 ` Ido Schimmel [this message]
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