From: Taehee Yoo <ap420073@gmail.com>
To: Sabrina Dubroca <sd@queasysnail.net>
Cc: "David Miller" <davem@davemloft.net>,
Netdev <netdev@vger.kernel.org>,
linux-wireless@vger.kernel.org,
"Jakub Kicinski" <jakub.kicinski@netronome.com>,
"Johannes Berg" <johannes@sipsolutions.net>,
j.vosburgh@gmail.com, vfalico@gmail.com,
"Andy Gospodarek" <andy@greyhouse.net>,
"Jiří Pírko" <jiri@resnulli.us>,
"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 01/12] net: core: limit nested device depth
Date: Sat, 12 Oct 2019 20:42:09 +0900 [thread overview]
Message-ID: <CAMArcTWEbH5=UKRSrw0-QR+dyT2GCJf3sjUA=eKVOEUJ3Wj8gQ@mail.gmail.com> (raw)
In-Reply-To: <20191010101925.GA93190@bistromath.localdomain>
On Thu, 10 Oct 2019 at 19:19, Sabrina Dubroca <sd@queasysnail.net> wrote:
>
Hi Sabrina,
Thank you for review and testing!
> 2019-09-28, 16:48:32 +0000, Taehee Yoo wrote:
> > @@ -6790,23 +6878,45 @@ int netdev_walk_all_lower_dev(struct net_device *dev,
> > void *data),
> > void *data)
> > {
> > - struct net_device *ldev;
> > - struct list_head *iter;
> > - int ret;
> > + struct net_device *ldev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
> > + struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
> > + int ret, cur = 0;
> >
> > - for (iter = &dev->adj_list.lower,
> > - ldev = netdev_next_lower_dev(dev, &iter);
> > - ldev;
> > - ldev = netdev_next_lower_dev(dev, &iter)) {
> > - /* first is the lower device itself */
> > - ret = fn(ldev, data);
> > - if (ret)
> > - return ret;
> > + now = dev;
> > + iter = &dev->adj_list.lower;
> >
> > - /* then look at all of its lower devices */
> > - ret = netdev_walk_all_lower_dev(ldev, fn, data);
> > - if (ret)
> > - return ret;
> > + while (1) {
> > + if (now != dev) {
> > + ret = fn(now, data);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + next = NULL;
> > + while (1) {
> > + ldev = netdev_next_lower_dev(now, &iter);
> > + if (!ldev)
> > + break;
> > +
> > + if (!next) {
> > + next = ldev;
> > + niter = &ldev->adj_list.lower;
> > + } else {
> > + dev_stack[cur] = ldev;
> > + iter_stack[cur++] = &ldev->adj_list.lower;
> > + break;
> > + }
> > + }
> > +
> > + if (!next) {
> > + if (!cur)
> > + return 0;
>
> Hmm, I don't think this condition is correct.
>
> If we have this topology:
>
>
> bridge0
> / | \
> / | \
> / | \
> dummy0 vlan1 vlan2
> | \
> dummy1 dummy2
>
> We end up with the expected lower/upper levels for all devices:
>
> | device | upper | lower |
> |---------+-------+-------|
> | dummy0 | 2 | 1 |
> | dummy1 | 3 | 1 |
> | dummy2 | 3 | 1 |
> | vlan1 | 2 | 2 |
> | vlan2 | 2 | 2 |
> | bridge0 | 1 | 3 |
>
>
> If we then add macvlan0 on top of bridge0:
>
>
> macvlan0
> |
> |
> bridge0
> / | \
> / | \
> / | \
> dummy0 vlan1 vlan2
> | \
> dummy1 dummy2
>
>
> we can observe that __netdev_update_upper_level is only called for
> some of the devices under bridge0. I added a perf probe:
>
> # perf probe -a '__netdev_update_upper_level dev->name:string'
>
> which gets hit for bridge0 (called directly by
> __netdev_upper_dev_link) and then dummy0, vlan1, dummy1. It is never
> called for vlan2 and dummy2.
>
> After this, we have the following levels (*):
>
> | device | upper | lower |
> |----------+-------+-------|
> | dummy0 | 3 | 1 |
> | dummy1 | 4 | 1 |
> | dummy2 | 3 | 1 |
> | vlan1 | 3 | 2 |
> | vlan2 | 2 | 2 |
> | bridge0 | 2 | 3 |
> | macvlan0 | 1 | 4 |
>
> For dummy0, dummy1, vlan1, the upper level has increased by 1, as
> expected. For dummy2 and vlan2, it's still the same, which is wrong.
>
>
> (*) observed easily by adding another probe:
>
> # perf probe -a 'dev_get_stats dev->name:string dev->upper_level dev->lower_level'
>
> and running "ip link"
>
> Or you can just add prints and recompile, of course :)
>
Thank you so much, I found a bug very easily with your test config.
I will fix this bug in a v5 patch.
> > + next = dev_stack[--cur];
> > + niter = iter_stack[cur];
> > + }
> > +
> > + now = next;
> > + iter = niter;
> > }
> >
> > return 0;
>
> --
> Sabrina
Thank you,
Taehee Yoo
next prev parent reply other threads:[~2019-10-12 11:44 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 [this message]
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
2019-10-01 7:39 ` Johannes Berg
2019-10-05 9:40 ` Taehee Yoo
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