From: Taehee Yoo <ap420073@gmail.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: "David Miller" <davem@davemloft.net>,
Netdev <netdev@vger.kernel.org>,
linux-wireless@vger.kernel.org,
"Jakub Kicinski" <jakub.kicinski@netronome.com>,
j.vosburgh@gmail.com, vfalico@gmail.com,
"Andy Gospodarek" <andy@greyhouse.net>,
"Jiří Pírko" <jiri@resnulli.us>,
sd@queasysnail.net, "Roopa Prabhu" <roopa@cumulusnetworks.com>,
saeedm@mellanox.com, manishc@marvell.com, rahulv@marvell.com,
kys@microsoft.com, haiyangz@microsoft.com,
"Stephen Hemminger" <stephen@networkplumber.org>,
sashal@kernel.org, hare@suse.de, varun@chelsio.com,
ubraun@linux.ibm.com, kgraul@linux.ibm.com,
"Jay Vosburgh" <jay.vosburgh@canonical.com>,
"Cody Schuffelen" <schuffelen@google.com>,
bjorn@mork.no
Subject: Re: [PATCH net v4 00/12] net: fix nested device bugs
Date: Sun, 29 Sep 2019 17:31:15 +0900 [thread overview]
Message-ID: <CAMArcTWs3wzad7ai_zQPCwzC62cFp-poELn+jnDaP7eT1a9ucw@mail.gmail.com> (raw)
In-Reply-To: <2e836018c7ea299037d732e5138ca395bd1ae50f.camel@sipsolutions.net>
On Sun, 29 Sep 2019 at 04:20, Johannes Berg <johannes@sipsolutions.net> wrote:
>
>
> > VLAN, BONDING, TEAM, MACSEC, MACVLAN, IPVLAN, VIRT_WIFI and VXLAN.
> > But I couldn't test all interface types so there could be more device
> > types which have similar problems.
>
> Did you test virt_wifi? I don't see how it *doesn't* have the nesting
> problem, and you didn't change it?
>
> No, I see. You're limiting the nesting generally now in patch 1, and the
> others are just lockdep fixups (I guess it's surprising virt_wifi
> doesn't do this at all?).
virt_wifi case is a little bit different case.
I add the last patch that is to fix refcnt leaks in the virt_wifi module.
The way to fix this is to add notifier routine.
The notifier routine could delete lower device before deleting
virt_wifi device.
If virt_wifi devices are nested, notifier would work recursively.
At that time, it would make stack memory overflow.
Actually, before this patch, virt_wifi doesn't have the same problem.
So, I will update a comment in a v5 patch.
>
> FWIW I don't think virt_wifi really benefits at all from stacking, so we
> could just do something like
>
> --- a/drivers/net/wireless/virt_wifi.c
> +++ b/drivers/net/wireless/virt_wifi.c
> @@ -508,6 +508,9 @@ static int virt_wifi_newlink(struct net *src_net, struct net_device *dev,
> else if (dev->mtu > priv->lowerdev->mtu)
> return -EINVAL;
>
> + if (priv->lowerdev->ieee80211_ptr)
> + return -EINVAL;
> +
> err = netdev_rx_handler_register(priv->lowerdev, virt_wifi_rx_handler,
> priv);
> if (err) {
>
Many other devices use this way to avoid wrong nesting configuration.
And I think it's a good way.
But we should think about the below configuration.
vlan5
|
virt_wifi4
|
vlan3
|
virt_wifi2
|
vlan1
|
dummy0
That code wouldn't avoid this configuration.
And all devices couldn't avoid this config.
I have been considering this case, but I couldn't make a decision yet.
Maybe common netdev function is needed to find the same device type
in their graph.
>
>
> IMHO, but of course generally limiting the stack depth is needed anyway
> and solves the problem well enough for virt_wifi.
>
>
This is a little bit different question for you.
I found another bug in virt_wifi after my last patch.
Please test below commands
ip link add dummy0 type dummy
ip link add vw1 link dummy0 type virt_wifi
ip link add vw2 link vw1 type virt_wifi
modprobe -rv virt_wifi
Then, you can see the warning messages.
If SET_NETDEV_DEV() is deleted in the virt_wifi_newlink(),
you can avoid that warning message.
But I'm not sure about it's safe to remove that.
I would really appreciate it if you let me know about that.
> johannes
>
next prev parent reply other threads:[~2019-09-29 8:31 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-28 16:48 [PATCH net v4 00/12] net: fix nested device bugs Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 01/12] net: core: limit nested device depth Taehee Yoo
2019-09-28 19:36 ` Johannes Berg
2019-09-29 11:05 ` Taehee Yoo
2019-10-01 7:11 ` Johannes Berg
2019-10-01 13:53 ` Taehee Yoo
2019-10-01 13:57 ` Johannes Berg
2019-10-01 18:23 ` Taehee Yoo
2019-10-10 10:19 ` Sabrina Dubroca
2019-10-12 11:42 ` Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 02/12] vlan: use dynamic lockdep key instead of subclass Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 03/12] bonding: fix unexpected IFF_BONDING bit unset Taehee Yoo
2019-09-30 20:48 ` Jay Vosburgh
2019-09-28 16:48 ` [PATCH net v4 04/12] bonding: use dynamic lockdep key instead of subclass Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 05/12] team: use dynamic lockdep key instead of static key Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 06/12] macsec: use dynamic lockdep key instead of subclass Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 07/12] macvlan: " Taehee Yoo
2019-09-28 19:14 ` Johannes Berg
2019-09-29 8:03 ` Taehee Yoo
2019-10-01 7:25 ` Johannes Berg
2019-10-05 9:13 ` Taehee Yoo
2019-10-07 11:41 ` Johannes Berg
2019-10-08 8:13 ` Taehee Yoo
2019-10-21 16:00 ` Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 08/12] macsec: fix refcnt leak in module exit routine Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 09/12] net: core: add ignore flag to netdev_adjacent structure Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 10/12] vxlan: add adjacent link to limit depth level Taehee Yoo
2019-09-28 16:48 ` [PATCH net v4 11/12] net: remove unnecessary variables and callback Taehee Yoo
2019-09-28 19:42 ` Johannes Berg
2019-09-28 16:48 ` [PATCH net v4 12/12] virt_wifi: fix refcnt leak in module exit routine Taehee Yoo
2019-09-28 18:57 ` Johannes Berg
2019-10-07 11:22 ` Sabrina Dubroca
2019-10-08 6:53 ` Taehee Yoo
2019-09-28 19:20 ` [PATCH net v4 00/12] net: fix nested device bugs Johannes Berg
2019-09-29 8:31 ` Taehee Yoo [this message]
2019-10-01 7:39 ` Johannes Berg
2019-10-05 9:40 ` Taehee Yoo
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