From: Saeed Mahameed <saeed@kernel.org>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
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>,
Eric Dumazet <edumazet@google.com>,
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@resnulli.us>, Florian Westphal <fw@strlen.de>,
Nikolay Aleksandrov <nikolay@nvidia.com>,
Pravin B Shelar <pshelar@ovn.org>,
Sridhar Samudrala <sridhar.samudrala@intel.com>
Subject: Re: [PATCH v6 net-next 11/15] net: catch errors from dev_get_stats
Date: Mon, 11 Jan 2021 15:51:39 -0800 [thread overview]
Message-ID: <6a6f5e835255a196f461b0e63a68b9bfa576ca1f.camel@kernel.org> (raw)
In-Reply-To: <20210111231535.lfkv7ggjzynbiicc@skbuf>
On Tue, 2021-01-12 at 01:15 +0200, Vladimir Oltean wrote:
> On Mon, Jan 11, 2021 at 02:54:50PM -0800, Saeed Mahameed wrote:
> > On Sat, 2021-01-09 at 19:26 +0200, Vladimir Oltean wrote:
> > > From: Vladimir Oltean <vladimir.oltean@nxp.com>
> > >
> > > dev_get_stats can now return error codes. Convert all remaining
> > > call
> > > sites to look at that error code and stop processing.
> > >
> > > The effects of simulating a kernel error (returning -ENOMEM) upon
> > > existing programs or kernel interfaces:
> > >
> > > - ifconfig and "cat /proc/net/dev" print up until the interface
> > > that
> > > failed, and there they return:
> > > cat: read error: Cannot allocate memory
> > >
> > > - ifstat and "ip -s -s link show":
> > > RTNETLINK answers: Cannot allocate memory
> > > Dump terminated
> > >
> > > Some call sites are coming from a context that returns void
> > > (ethtool
> > > stats, workqueue context). So since we can't report to the upper
> > > layer,
> > > do the next best thing: print an error to the console.
> > >
> >
> > another concern, one buggy netdev driver in a system will cause
> > unnecessary global failures when reading stats via netlink/procfs
> > for
> > all the netdev in a netns, when other drivers will be happy to
> > report.
> >
> > can't we just show a message in that driver's stats line about the
> > occurred err ? and show the normal stats line of all others ?
>
> So you're worried that user space apps won't handle an error code
> when
> reading from a file, but you're not worried that they'll start
> scraping
> junk from procfs when we print this?
>
both are equivalently concerning.
to avoid any user crashes, we can just toss failed netdevs out from the
output.
> cat /proc/net/dev
> Inter-
> | Receive | Transmi
> t
> face |bytes packets errs drop fifo frame compressed
> multicast|bytes packets errs drop fifo colls carrier compressed
> lo: 0 0 0 0 0 0 0 0
> 0 0 0 0 0 0 0 0
> bond0: Cannot allocate memory
>
> sit0: 0 0 0 0 0 0 0 0
> 0 0 0 0 0 0 0 0
next prev parent reply other threads:[~2021-01-12 0:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-09 17:26 [PATCH v6 net-next 00/15] Make .ndo_get_stats64 sleepable Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 01/15] net: mark dev_base_lock for deprecation Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 02/15] net: introduce a mutex for the netns interface lists Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 03/15] net: procfs: hold netif_lists_lock when retrieving device statistics Vladimir Oltean
2021-01-11 23:46 ` Saeed Mahameed
2021-01-12 13:44 ` Vladimir Oltean
2021-01-12 20:06 ` Saeed Mahameed
2021-01-09 17:26 ` [PATCH v6 net-next 04/15] net: sysfs: don't hold dev_base_lock while " Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 05/15] s390/appldata_net_sum: hold the netdev lists lock when " Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 06/15] parisc/led: " Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 07/15] net: remove return value from dev_get_stats Vladimir Oltean
2021-01-11 22:08 ` Saeed Mahameed
2021-01-09 17:26 ` [PATCH v6 net-next 08/15] net: allow ndo_get_stats64 to return an int error code Vladimir Oltean
2021-01-11 22:24 ` Saeed Mahameed
2021-01-11 22:43 ` Saeed Mahameed
2021-01-09 17:26 ` [PATCH v6 net-next 09/15] scsi: fcoe: propagate errors from dev_get_stats Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 10/15] net: openvswitch: " Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 11/15] net: catch " Vladimir Oltean
2021-01-11 22:54 ` Saeed Mahameed
2021-01-11 23:15 ` Vladimir Oltean
2021-01-11 23:51 ` Saeed Mahameed [this message]
2021-01-18 10:31 ` Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 12/15] net: openvswitch: ensure dev_get_stats can sleep Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 13/15] net: net_failover: ensure .ndo_get_stats64 " Vladimir Oltean
2021-01-09 17:26 ` [PATCH v6 net-next 14/15] net: bonding: " Vladimir Oltean
2021-01-11 23:38 ` Saeed Mahameed
2021-01-12 14:37 ` Vladimir Oltean
2021-01-12 20:10 ` Saeed Mahameed
2021-01-13 2:00 ` Jay Vosburgh
2021-01-09 17:26 ` [PATCH v6 net-next 15/15] net: mark ndo_get_stats64 as being able to sleep Vladimir Oltean
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