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From: Taehee Yoo <ap420073@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: Netdev <netdev@vger.kernel.org>,
	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,
	sthemmin@microsoft.com, sashal@kernel.org, hare@suse.de,
	varun@chelsio.com, ubraun@linux.ibm.com, kgraul@linux.ibm.com,
	"Jay Vosburgh" <jay.vosburgh@canonical.com>
Subject: Re: [PATCH net v2 01/11] net: core: limit nested device depth
Date: Thu, 12 Sep 2019 21:49:44 +0900	[thread overview]
Message-ID: <CAMArcTVtv=ah=KbzOb=u_Qyx0V+iGts77kz_X9GhJfEHbGPUSQ@mail.gmail.com> (raw)
In-Reply-To: <20190912.133717.257813019167130934.davem@davemloft.net>

On Thu, 12 Sep 2019 at 20:37, David Miller <davem@davemloft.net> wrote:
>
> From: Taehee Yoo <ap420073@gmail.com>
> Date: Thu, 12 Sep 2019 19:14:37 +0900
>
> > On Thu, 12 Sep 2019 at 18:38, David Miller <davem@davemloft.net> wrote:
> >>
> >> From: Taehee Yoo <ap420073@gmail.com>
> >> Date: Thu, 12 Sep 2019 12:56:19 +0900
> >>
> >> > I tested with this reproducer commands without lockdep.
> >> >
> >> >     ip link add dummy0 type dummy
> >> >     ip link add link dummy0 name vlan1 type vlan id 1
> >> >     ip link set vlan1 up
> >> >
> >> >     for i in {2..200}
> >> >     do
> >> >             let A=$i-1
> >> >
> >> >             ip link add name vlan$i link vlan$A type vlan id $i
> >> >     done
> >> >     ip link del vlan1 <-- this command is added.
> >>
> >> Is there any other device type which allows arbitrary nesting depth
> >> in this manner other than VLAN?  Perhaps it is the VLAN nesting
> >> depth that we should limit instead of all of this extra code.
> >
> > Below device types have the same problem.
> > VLAN, BONDING, TEAM, VXLAN, MACVLAN, and MACSEC.
> > All the below test commands reproduce a panic.
>
> I think then we need to move the traversals over to a iterative
> rather than recursive algorithm.

Just to clarify, I have a question.

There are two recursive routines in the code.
a) netdev_walk_all_{lower/upper}_dev() that are used to traversal
all of their lower or upper devices.
b) VLAN, BONDING, TEAM, VXLAN, MACVLAN, and MACSEC
modules internally handle their lower/upper devices recursively
when an event is received such as unregistering.

what is the routine that you mentioned?

      parent reply	other threads:[~2019-09-12 12:50 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-07 13:45 [PATCH net v2 01/11] net: core: limit nested device depth Taehee Yoo
2019-09-11 22:32 ` David Miller
2019-09-12  3:56   ` Taehee Yoo
2019-09-12  9:38     ` David Miller
2019-09-12 10:14       ` Taehee Yoo
2019-09-12 11:37         ` David Miller
2019-09-12 11:54           ` Taehee Yoo
2019-09-12 12:49           ` Taehee Yoo [this message]

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