From: Jakub Kicinski <kuba@kernel•org>
To: <sdf@fomichev•me>
Cc: Kuniyuki Iwashima <kuniyu@amazon•com>, <andrew+netdev@lunn•ch>,
<davem@davemloft•net>, <edumazet@google•com>, <horms@kernel•org>,
<hramamurthy@google•com>, <jdamato@fastly•com>,
<netdev@vger•kernel.org>, <pabeni@redhat•com>
Subject: Re: [PATCH net-next v2 6/8] netdev: depend on netdev->lock for xdp features
Date: Thu, 10 Apr 2025 19:23:26 -0700 [thread overview]
Message-ID: <20250410192326.0a5dbb10@kernel.org> (raw)
In-Reply-To: <20250410191028.31a0eaf2@kernel.org>
On Thu, 10 Apr 2025 19:10:28 -0700 Jakub Kicinski wrote:
> On Thu, 10 Apr 2025 10:10:01 -0700 Kuniyuki Iwashima wrote:
> > syzkaller reported splats in register_netdevice() and
> > unregister_netdevice_many_notify().
> >
> > In register_netdevice(), some devices cannot use
> > netdev_assert_locked().
> >
> > In unregister_netdevice_many_notify(), maybe we need to
> > hold ops lock in UNREGISTER as you initially suggested.
> > Now do_setlink() deadlock does not happen.
>
> Ah... Thank you.
>
> Do you have a reference to use as Reported-by, or its from a
> non-public instance ?
>
> I'll test this shortly:
>
> diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
> index b64c614a00c4..891e2f60922f 100644
> --- a/net/core/netdev-genl.c
> +++ b/net/core/netdev-genl.c
> @@ -38,7 +38,8 @@ netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
> u64 xdp_rx_meta = 0;
> void *hdr;
>
> - netdev_assert_locked(netdev); /* note: rtnl_lock may not be held! */
> + /* note: rtnl_lock may or may not be held! */
> + netdev_assert_locked_or_invisible(netdev);
>
> hdr = genlmsg_iput(rsp, info);
> if (!hdr)
> @@ -966,7 +967,9 @@ static int netdev_genl_netdevice_event(struct notifier_block *nb,
> netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_ADD_NTF);
> break;
> case NETDEV_UNREGISTER:
> + netdev_lock(netdev);
> netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_DEL_NTF);
> + netdev_unlock(netdev);
> break;
> case NETDEV_XDP_FEAT_CHANGE:
> netdev_genl_dev_notify(netdev, NETDEV_CMD_DEV_CHANGE_NTF);
Ugh, REGISTER is ops locked we'd need conditional locking here.
Stanislav, I can make the REGISTERED notifier fully locked, right?
I suspect any new object we add that's protected by the instance
lock will want to lock the dev.
next prev parent reply other threads:[~2025-04-11 2:23 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-08 19:59 [PATCH net-next v2 0/8] net: depend on instance lock for queue related netlink ops Jakub Kicinski
2025-04-08 19:59 ` [PATCH net-next v2 1/8] net: avoid potential race between netdev_get_by_index_lock() and netns switch Jakub Kicinski
2025-04-08 19:59 ` [PATCH net-next v2 2/8] net: designate XSK pool pointers in queues as "ops protected" Jakub Kicinski
2025-04-08 19:59 ` [PATCH net-next v2 3/8] netdev: add "ops compat locking" helpers Jakub Kicinski
2025-04-08 19:59 ` [PATCH net-next v2 4/8] netdev: don't hold rtnl_lock over nl queue info get when possible Jakub Kicinski
2025-04-08 19:59 ` [PATCH net-next v2 5/8] xdp: double protect netdev->xdp_flags with netdev->lock Jakub Kicinski
2025-04-08 22:15 ` Harshitha Ramamurthy
2025-04-09 18:40 ` Martin KaFai Lau
2025-04-08 19:59 ` [PATCH net-next v2 6/8] netdev: depend on netdev->lock for xdp features Jakub Kicinski
2025-04-10 17:10 ` Kuniyuki Iwashima
2025-04-11 2:10 ` Jakub Kicinski
2025-04-11 2:23 ` Jakub Kicinski [this message]
2025-04-11 17:41 ` Stanislav Fomichev
2025-04-11 19:19 ` Jakub Kicinski
2025-04-11 2:36 ` Kuniyuki Iwashima
2025-04-08 19:59 ` [PATCH net-next v2 7/8] docs: netdev: break down the instance locking info per ops struct Jakub Kicinski
2025-04-09 2:59 ` Joe Damato
2025-04-10 6:01 ` Jacob Keller
2025-04-10 16:08 ` Jakub Kicinski
2025-04-10 22:35 ` Keller, Jacob E
2025-04-10 23:39 ` Jakub Kicinski
2025-04-11 21:26 ` Jacob Keller
2025-04-08 19:59 ` [PATCH net-next v2 8/8] netdev: depend on netdev->lock for qstats in ops locked drivers Jakub Kicinski
2025-04-10 5:23 ` Jacob Keller
2025-04-10 23:46 ` Jakub Kicinski
2025-04-11 21:29 ` Jacob Keller
2025-04-10 0:40 ` [PATCH net-next v2 0/8] net: depend on instance lock for queue related netlink ops patchwork-bot+netdevbpf
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