From: Eric Dumazet <edumazet@google.com>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, netdev <netdev@vger.kernel.org>,
Andrew Lunn <andrew@lunn.ch>,
Florian Fainelli <f.fainelli@gmail.com>,
Cong Wang <xiyou.wangcong@gmail.com>,
Stephen Hemminger <stephen@networkplumber.org>,
George McCollister <george.mccollister@gmail.com>,
Oleksij Rempel <o.rempel@pengutronix.de>,
Jay Vosburgh <j.vosburgh@gmail.com>,
Veaceslav Falico <vfalico@gmail.com>,
Andy Gospodarek <andy@greyhouse.net>,
Arnd Bergmann <arnd@arndb.de>, Taehee Yoo <ap420073@gmail.com>,
Jiri Pirko <jiri@mellanox.com>, Florian Westphal <fw@strlen.de>
Subject: Re: [PATCH v3 net-next 10/12] net: bonding: ensure .ndo_get_stats64 can sleep
Date: Thu, 7 Jan 2021 12:18:28 +0100 [thread overview]
Message-ID: <CANn89i+NfBw7ZpL-DTDA3QGBK=neT2R7qKYn_pcvDmRAOkaUsQ@mail.gmail.com> (raw)
In-Reply-To: <20210107094951.1772183-11-olteanv@gmail.com>
On Thu, Jan 7, 2021 at 10:51 AM Vladimir Oltean <olteanv@gmail.com> wrote:
>
> From: Vladimir Oltean <vladimir.oltean@nxp.com>
>
>
-
> static void bond_get_stats(struct net_device *bond_dev,
> struct rtnl_link_stats64 *stats)
> {
> struct bonding *bond = netdev_priv(bond_dev);
> - struct rtnl_link_stats64 temp;
> - struct list_head *iter;
> - struct slave *slave;
> - int nest_level = 0;
> + struct rtnl_link_stats64 *dev_stats;
> + struct net_device **slaves;
> + int i, res, num_slaves;
>
> + res = bond_get_slave_arr(bond, &slaves, &num_slaves);
> + if (res) {
> + netdev_err(bond->dev,
> + "failed to allocate memory for slave array\n");
> + return;
> + }
>
What a mess really.
You chose to keep the assumption that ndo_get_stats() would not fail,
since we were providing the needed storage from callers.
If ndo_get_stats() are now allowed to sleep, and presumably allocate
memory, we need to make sure
we report potential errors back to the user.
I think your patch series is mostly good, but I would prefer not
hiding errors and always report them to user space.
And no, netdev_err() is not appropriate, we do not want tools to look
at syslog to guess something went wrong.
Last point about drivers having to go to slow path, talking to
firmware : Make sure that malicious/innocent users
reading /proc/net/dev from many threads in parallel wont brick these devices.
Maybe they implicitly _relied_ on the fact that firmware was gently
read every second and results were cached from a work queue or
something.
Thanks.
next prev parent reply other threads:[~2021-01-07 11:19 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 9:49 [PATCH v3 net-next 00/12] Make .ndo_get_stats64 sleepable Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 01/12] net: mark dev_base_lock for deprecation Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 02/12] net: introduce a mutex for the netns interface lists Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 03/12] net: procfs: hold netif_lists_lock when retrieving device statistics Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 04/12] net: sysfs: don't hold dev_base_lock while " Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 05/12] s390/appldata_net_sum: hold the netdev lists lock when " Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 06/12] parisc/led: reindent the code that gathers " Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 07/12] parisc/led: hold the netdev lists lock when retrieving " Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 08/12] net: make dev_get_stats return void Vladimir Oltean
2021-01-07 13:01 ` kernel test robot
2021-01-07 13:15 ` Vladimir Oltean
2021-01-08 0:50 ` Rong Chen
2021-01-07 9:49 ` [PATCH v3 net-next 09/12] net: net_failover: ensure .ndo_get_stats64 can sleep Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 10/12] net: bonding: " Vladimir Oltean
2021-01-07 11:18 ` Eric Dumazet [this message]
2021-01-07 11:33 ` Vladimir Oltean
2021-01-07 12:58 ` Eric Dumazet
2021-01-08 3:59 ` Saeed Mahameed
2021-01-08 8:57 ` Vladimir Oltean
2021-01-08 19:25 ` Saeed Mahameed
2021-01-08 9:14 ` Eric Dumazet
2021-01-08 9:21 ` Vladimir Oltean
2021-01-08 9:27 ` Eric Dumazet
2021-01-08 19:38 ` Saeed Mahameed
2021-01-08 20:20 ` Vladimir Oltean
2021-01-08 19:33 ` Saeed Mahameed
2021-01-07 9:49 ` [PATCH v3 net-next 11/12] net: mark ndo_get_stats64 as being able to sleep Vladimir Oltean
2021-01-07 9:49 ` [PATCH v3 net-next 12/12] net: remove obsolete comments about ndo_get_stats64 context from eth drivers Vladimir Oltean
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