From: Joe Damato <joe@dama.to>
To: Maoyi Xie <maoyixie.tju@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Nikolay Aleksandrov <razor@blackwall.org>,
David Wei <dw@davidwei.uk>, Stanislav Fomichev <sdf@fomichev.me>,
Dragos Tatulea <dtatulea@nvidia.com>,
Samiullah Khawaja <skhawaja@google.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH net] netdev-genl: report NAPI thread PID in the caller's pid namespace
Date: Mon, 15 Jun 2026 13:43:18 -0700 [thread overview]
Message-ID: <ajBj5j01YmdS02Uw@devvm20253.cco0.facebook.com> (raw)
In-Reply-To: <20260615171736.1709318-1-maoyixie.tju@gmail.com>
On Tue, Jun 16, 2026 at 01:17:36AM +0800, Maoyi Xie wrote:
> netdev_nl_napi_fill_one() reports the NAPI kthread PID in NETDEV_A_NAPI_PID
> using task_pid_nr(), which returns the PID in the initial pid namespace.
>
> NETDEV_CMD_NAPI_GET does not have GENL_ADMIN_PERM and the netdev genl family
> is netnsok, so a caller in a child pid namespace can issue it. That caller
> then sees the kthread's global PID, even though the kthread is not visible
> in its pid namespace, where the value should be 0.
>
> Translate the PID through the caller's pid namespace, the same way commit
> 3799c2570982 ("io_uring/fdinfo: translate SqThread PID through caller's
> pid_ns") did for the io_uring SQPOLL thread. The doit and dumpit paths both
> run synchronously in the caller's context, so task_active_pid_ns(current) is
> the caller's pid namespace.
>
> Fixes: db4704f4e4df ("netdev-genl: Add PID for the NAPI thread")
> Cc: stable@vger.kernel.org
> Signed-off-by: Maoyi Xie <maoyixie.tju@gmail.com>
> ---
> net/core/netdev-genl.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
Reviewed-by: Joe Damato <joe@dama.to>
next prev parent reply other threads:[~2026-06-15 20:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-15 17:17 [PATCH net] netdev-genl: report NAPI thread PID in the caller's pid namespace Maoyi Xie
2026-06-15 20:43 ` Joe Damato [this message]
2026-06-16 0:27 ` Samiullah Khawaja
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