Commits · 853697504de043ff0bfd815bd3a64de1dce73dc7 · Kirill Smelkov / linux

31 Dec, 2019 7 commits

tcp: Fix highest_sack and highest_sack_seq · 85369750

Cambda Zhu authored Dec 27, 2019

>From commit 50895b9d ("tcp: highest_sack fix"), the logic about
setting tp->highest_sack to the head of the send queue was removed.
Of course the logic is error prone, but it is logical. Before we
remove the pointer to the highest sack skb and use the seq instead,
we need to set tp->highest_sack to NULL when there is no skb after
the last sack, and then replace NULL with the real skb when new skb
inserted into the rtx queue, because the NULL means the highest sack
seq is tp->snd_nxt. If tp->highest_sack is NULL and new data sent,
the next ACK with sack option will increase tp->reordering unexpectedly.

This patch sets tp->highest_sack to the tail of the rtx queue if
it's NULL and new data is sent. The patch keeps the rule that the
highest_sack can only be maintained by sack processing, except for
this only case.

Fixes: 50895b9d ("tcp: highest_sack fix")
Signed-off-by: Cambda Zhu <cambda@linux.alibaba.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

85369750

ptp: fix the race between the release of ptp_clock and cdev · a33121e5

Vladis Dronov authored Dec 27, 2019

In a case when a ptp chardev (like /dev/ptp0) is open but an underlying
device is removed, closing this file leads to a race. This reproduces
easily in a kvm virtual machine:

ts# cat openptp0.c
int main() { ... fp = fopen("/dev/ptp0", "r"); ... sleep(10); }
ts# uname -r
5.5.0-rc3-46cf053e
ts# cat /proc/cmdline
... slub_debug=FZP
ts# modprobe ptp_kvm
ts# ./openptp0 &
[1] 670
opened /dev/ptp0, sleeping 10s...
ts# rmmod ptp_kvm
ts# ls /dev/ptp*
ls: cannot access '/dev/ptp*': No such file or directory
ts# ...woken up
[   48.010809] general protection fault: 0000 [#1] SMP
[   48.012502] CPU: 6 PID: 658 Comm: openptp0 Not tainted 5.5.0-rc3-46cf053e #25
[   48.014624] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...
[   48.016270] RIP: 0010:module_put.part.0+0x7/0x80
[   48.017939] RSP: 0018:ffffb3850073be00 EFLAGS: 00010202
[   48.018339] RAX: 000000006b6b6b6b RBX: 6b6b6b6b6b6b6b6b RCX: ffff89a476c00ad0
[   48.018936] RDX: fffff65a08d3ea08 RSI: 0000000000000247 RDI: 6b6b6b6b6b6b6b6b
[   48.019470] ...                                              ^^^ a slub poison
[   48.023854] Call Trace:
[   48.024050]  __fput+0x21f/0x240
[   48.024288]  task_work_run+0x79/0x90
[   48.024555]  do_exit+0x2af/0xab0
[   48.024799]  ? vfs_write+0x16a/0x190
[   48.025082]  do_group_exit+0x35/0x90
[   48.025387]  __x64_sys_exit_group+0xf/0x10
[   48.025737]  do_syscall_64+0x3d/0x130
[   48.026056]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   48.026479] RIP: 0033:0x7f53b12082f6
[   48.026792] ...
[   48.030945] Modules linked in: ptp i6300esb watchdog [last unloaded: ptp_kvm]
[   48.045001] Fixing recursive fault but reboot is needed!

This happens in:

static void __fput(struct file *file)
{   ...
    if (file->f_op->release)
        file->f_op->release(inode, file); <<< cdev is kfree'd here
    if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL &&
             !(mode & FMODE_PATH))) {
        cdev_put(inode->i_cdev); <<< cdev fields are accessed here

Namely:

__fput()
  posix_clock_release()
    kref_put(&clk->kref, delete_clock) <<< the last reference
      delete_clock()
        delete_ptp_clock()
          kfree(ptp) <<< cdev is embedded in ptp
  cdev_put
    module_put(p->owner) <<< *p is kfree'd, bang!

Here cdev is embedded in posix_clock which is embedded in ptp_clock.
The race happens because ptp_clock's lifetime is controlled by two
refcounts: kref and cdev.kobj in posix_clock. This is wrong.

Make ptp_clock's sysfs device a parent of cdev with cdev_device_add()
created especially for such cases. This way the parent device with its
ptp_clock is not released until all references to the cdev are released.
This adds a requirement that an initialized but not exposed struct
device should be provided to posix_clock_register() by a caller instead
of a simple dev_t.

This approach was adopted from the commit 72139dfa ("watchdog: Fix
the race between the release of watchdog_core_data and cdev"). See
details of the implementation in the commit 233ed09d ("chardev: add
helper function to register char devs with a struct device").

Link: https://lore.kernel.org/linux-fsdevel/20191125125342.6189-1-vdronov@redhat.com/T/#uAnalyzed-by: Stephen Johnston <sjohnsto@redhat.com>
Analyzed-by: Vern Lovejoy <vlovejoy@redhat.com>
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

a33121e5

net: dsa: sja1105: Reconcile the meaning of TPID and TPID2 for E/T and P/Q/R/S · 54fa49ee

Vladimir Oltean authored Dec 27, 2019

For first-generation switches (SJA1105E and SJA1105T):
- TPID means C-Tag (typically 0x8100)
- TPID2 means S-Tag (typically 0x88A8)

While for the second generation switches (SJA1105P, SJA1105Q, SJA1105R,
SJA1105S) it is the other way around:
- TPID means S-Tag (typically 0x88A8)
- TPID2 means C-Tag (typically 0x8100)

In other words, E/T tags untagged traffic with TPID, and P/Q/R/S with
TPID2.

So the patch mentioned below fixed VLAN filtering for P/Q/R/S, but broke
it for E/T.

We strive for a common code path for all switches in the family, so just
lie in the static config packing functions that TPID and TPID2 are at
swapped bit offsets than they actually are, for P/Q/R/S. This will make
both switches understand TPID to be ETH_P_8021Q and TPID2 to be
ETH_P_8021AD. The meaning from the original E/T was chosen over P/Q/R/S
because E/T is actually the one with public documentation available
(UM10944.pdf).

Fixes: f9a1a764 ("net: dsa: sja1105: Reverse TPID and TPID2")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

54fa49ee

Documentation: net: dsa: sja1105: Remove text about taprio base-time limitation · 3a323ed7

Vladimir Oltean authored Dec 27, 2019

Since commit 86db36a3 ("net: dsa: sja1105: Implement state machine
for TAS with PTP clock source"), this paragraph is no longer true. So
remove it.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3a323ed7

net: dsa: sja1105: Remove restriction of zero base-time for taprio offload · d00bdc0a

Vladimir Oltean authored Dec 27, 2019

The check originates from the initial implementation which was not based
on PTP time but on a standalone clock source. In the meantime we can now
program the PTPSCHTM register at runtime with the dynamic base time
(actually with a value that is 200 ns smaller, to avoid writing DELTA=0
in the Schedule Entry Points Parameters Table). And we also have logic
for moving the actual base time in the future of the PHC's current time
base, so the check for zero serves no purpose, since even if the user
will specify zero, that's not what will end up in the static config
table where the limitation is.

Fixes: 86db36a3 ("net: dsa: sja1105: Implement state machine for TAS with PTP clock source")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

d00bdc0a

net: dsa: sja1105: Really make the PTP command read-write · 5a47f588

Vladimir Oltean authored Dec 27, 2019

When activating tc-taprio offload on the switch ports, the TAS state
machine will try to check whether it is running or not, but will find
both the STARTED and STOPPED bits as false in the
sja1105_tas_check_running function. So the function will return -EINVAL
(an abnormal situation) and the kernel will keep printing this from the
TAS FSM workqueue:

[   37.691971] sja1105 spi0.1: An operation returned -22

The reason is that the underlying function that gets called,
sja1105_ptp_commit, does not actually do a SPI_READ, but a SPI_WRITE. So
the command buffer remains initialized with zeroes instead of retrieving
the hardware state. Fix that.

Fixes: 41603d78 ("net: dsa: sja1105: Make the PTP command read-write")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5a47f588

net: dsa: sja1105: Take PTP egress timestamp by port, not mgmt slot · 9fcf024d

Vladimir Oltean authored Dec 27, 2019

The PTP egress timestamp N must be captured from register PTPEGR_TS[n],
where n = 2 * PORT + TSREG. There are 10 PTPEGR_TS registers, 2 per
port. We are only using TSREG=0.

As opposed to the management slots, which are 4 in number
(SJA1105_NUM_PORTS, minus the CPU port). Any management frame (which
includes PTP frames) can be sent to any non-CPU port through any
management slot. When the CPU port is not the last port (#4), there will
be a mismatch between the slot and the port number.

Luckily, the only mainline occurrence with this switch
(arch/arm/boot/dts/ls1021a-tsn.dts) does have the CPU port as #4, so the
issue did not manifest itself thus far.

Fixes: 47ed985e ("net: dsa: sja1105: Add logic for TX timestamping")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

9fcf024d

30 Dec, 2019 1 commit

cxgb4/cxgb4vf: fix flow control display for auto negotiation · 0caeaf6a

Rahul Lakkireddy authored Dec 30, 2019

As per 802.3-2005, Section Two, Annex 28B, Table 28B-2 [1], when
_only_ Rx pause is enabled, both symmetric and asymmetric pause
towards local device must be enabled. Also, firmware returns the local
device's flow control pause params as part of advertised capabilities
and negotiated params as part of current link attributes. So, fix up
ethtool's flow control pause params fetch logic to read from acaps,
instead of linkattr.

[1] https://standards.ieee.org/standard/802_3-2005.html

Fixes: c3168cab ("cxgb4/cxgbvf: Handle 32-bit fw port capabilities")
Signed-off-by: Surendra Mobiya <surendra@chelsio.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

0caeaf6a

29 Dec, 2019 3 commits

Merge branch 'mlxsw-fixes' · 3faf6eda

David S. Miller authored Dec 29, 2019

Ido Schimmel says:

====================
mlxsw: Couple of fixes

This patch set contains two fixes for mlxsw. Please consider both for
stable.

Patch #1 from Amit fixes a wrong check during MAC validation when
creating router interfaces (RIFs). Given a particular order of
configuration this can result in the driver refusing to create new RIFs.

Patch #2 fixes a wrong trap configuration in which VRRP packets and
routing exceptions were policed by the same policer towards the CPU. In
certain situations this can prevent VRRP packets from reaching the CPU.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

3faf6eda

mlxsw: spectrum: Use dedicated policer for VRRP packets · acca789a

Ido Schimmel authored Dec 29, 2019

Currently, VRRP packets and packets that hit exceptions during routing
(e.g., MTU error) are policed using the same policer towards the CPU.
This means, for example, that misconfiguration of the MTU on a routed
interface can prevent VRRP packets from reaching the CPU, which in turn
can cause the VRRP daemon to assume it is the Master router.

Fix this by using a dedicated policer for VRRP packets.

Fixes: 11566d34 ("mlxsw: spectrum: Add VRRP traps")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reported-by: Alex Veber <alexve@mellanox.com>
Tested-by: Alex Veber <alexve@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

acca789a

mlxsw: spectrum_router: Skip loopback RIFs during MAC validation · 314bd842

Amit Cohen authored Dec 29, 2019

When a router interface (RIF) is created the MAC address of the backing
netdev is verified to have the same MSBs as existing RIFs. This is
required in order to avoid changing existing RIF MAC addresses that all
share the same MSBs.

Loopback RIFs are special in this regard as they do not have a MAC
address, given they are only used to loop packets from the overlay to
the underlay.

Without this change, an error is returned when trying to create a RIF
after the creation of a GRE tunnel that is represented by a loopback
RIF. 'rif->dev->dev_addr' points to the GRE device's local IP, which
does not share the same MSBs as physical interfaces. Adding an IP
address to any physical interface results in:

Error: mlxsw_spectrum: All router interface MAC addresses must have the
same prefix.

Fix this by skipping loopback RIFs during MAC validation.

Fixes: 74bc9939 ("mlxsw: spectrum_router: Veto unsupported RIF MAC addresses")
Signed-off-by: Amit Cohen <amitc@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

314bd842

28 Dec, 2019 2 commits

net: stmmac: dwmac-meson8b: Fix the RGMII TX delay on Meson8b/8m2 SoCs · bd6f4854

Martin Blumenstingl authored Dec 26, 2019

GXBB and newer SoCs use the fixed FCLK_DIV2 (1GHz) clock as input for
the m250_sel clock. Meson8b and Meson8m2 use MPLL2 instead, whose rate
can be adjusted at runtime.

So far we have been running MPLL2 with ~250MHz (and the internal
m250_div with value 1), which worked enough that we could transfer data
with an TX delay of 4ns. Unfortunately there is high packet loss with
an RGMII PHY when transferring data (receiving data works fine though).
Odroid-C1's u-boot is running with a TX delay of only 2ns as well as
the internal m250_div set to 2 - no lost (TX) packets can be observed
with that setting in u-boot.

Manual testing has shown that the TX packet loss goes away when using
the following settings in Linux (the vendor kernel uses the same
settings):
- MPLL2 clock set to ~500MHz
- m250_div set to 2
- TX delay set to 2ns on the MAC side

Update the m250_div divider settings to only accept dividers greater or
equal 2 to fix the TX delay generated by the MAC.

iperf3 results before the change:
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec   182 MBytes   153 Mbits/sec  514      sender
[  5]   0.00-10.00  sec   182 MBytes   152 Mbits/sec           receiver

iperf3 results after the change (including an updated TX delay of 2ns):
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-10.00  sec   927 MBytes   778 Mbits/sec    0      sender
[  5]   0.00-10.01  sec   927 MBytes   777 Mbits/sec           receiver

Fixes: 4f6a71b8 ("net: stmmac: dwmac-meson8b: fix internal RGMII clock configuration")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

bd6f4854

net/sched: act_mirred: Pull mac prior redir to non mac_header_xmit device · 70cf3dc7

Shmulik Ladkani authored Dec 25, 2019

There's no skb_pull performed when a mirred action is set at egress of a
mac device, with a target device/action that expects skb->data to point
at the network header.

As a result, either the target device is errornously given an skb with
data pointing to the mac (egress case), or the net stack receives the
skb with data pointing to the mac (ingress case).

E.g:
 # tc qdisc add dev eth9 root handle 1: prio
 # tc filter add dev eth9 parent 1: prio 9 protocol ip handle 9 basic \
   action mirred egress redirect dev tun0

 (tun0 is a tun device. result: tun0 errornously gets the eth header
  instead of the iph)

Revise the push/pull logic of tcf_mirred_act() to not rely on the
skb_at_tc_ingress() vs tcf_mirred_act_wants_ingress() comparison, as it
does not cover all "pull" cases.

Instead, calculate whether the required action on the target device
requires the data to point at the network header, and compare this to
whether skb->data points to network header - and make the push/pull
adjustments as necessary.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Shmulik Ladkani <sladkani@proofpoint.com>
Tested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

70cf3dc7

26 Dec, 2019 18 commits

net_sched: sch_fq: properly set sk->sk_pacing_status · bb3d0b8b

Eric Dumazet authored Dec 23, 2019

If fq_classify() recycles a struct fq_flow because
a socket structure has been reallocated, we do not
set sk->sk_pacing_status immediately, but later if the
flow becomes detached.

This means that any flow requiring pacing (BBR, or SO_MAX_PACING_RATE)
might fallback to TCP internal pacing, which requires a per-socket
high resolution timer, and therefore more cpu cycles.

Fixes: 218af599 ("tcp: internal implementation for pacing")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

bb3d0b8b

Merge branch 'bnx2x-Bug-fixes' · 4e55a11a

David S. Miller authored Dec 26, 2019

Manish Chopra says:

====================
bnx2x: Bug fixes

This series has changes in the area of vlan resources
management APIs to fix fw assert issue reported in max
vlan configuration testing over the PF.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

4e55a11a

bnx2x: Fix accounting of vlan resources among the PFs · 5cdc40c7

Manish Chopra authored Dec 23, 2019

While testing max vlan configuration on the PF, firmware gets
assert as driver was configuring number of vlans more than what
is supported per port/engine, it was figured out that there is an
implicit vlan (hidden default vlan consuming hardware cam entry resource)
which is configured default for all the clients (PF/VFs) on client_init
ramrod by the adapter implicitly, so when allocating resources among the
PFs this implicit vlan should be considered or total vlan entries should
be reduced by one to accommodate that default/implicit vlan entry.
Signed-off-by: Manish Chopra <manishc@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5cdc40c7

bnx2x: Use appropriate define for vlan credit · 0444716a

Manish Chopra authored Dec 23, 2019

Although it has same value as MAX_MAC_CREDIT_E2,
use MAX_VLAN_CREDIT_E2 appropriately.
Signed-off-by: Manish Chopra <manishc@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

0444716a

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf · 3c2f450e

David S. Miller authored Dec 26, 2019

Daniel Borkmann says:

====================
pull-request: bpf 2019-12-23

The following pull-request contains BPF updates for your *net* tree.

We've added 2 non-merge commits during the last 1 day(s) which contain
a total of 4 files changed, 34 insertions(+), 31 deletions(-).

The main changes are:

1) Fix libbpf build when building on a read-only filesystem with O=dir
   option, from Namhyung Kim.

2) Fix a precision tracking bug for unknown scalars, from Daniel Borkmann.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

3c2f450e

of: mdio: Add missing inline to of_mdiobus_child_is_phy() dummy · 7df2281a

Geert Uytterhoeven authored Dec 23, 2019

If CONFIG_OF_MDIO=n:

    drivers/net/phy/mdio_bus.c:23:
    include/linux/of_mdio.h:58:13: warning: ‘of_mdiobus_child_is_phy’ defined but not used [-Wunused-function]
     static bool of_mdiobus_child_is_phy(struct device_node *child)
		 ^~~~~~~~~~~~~~~~~~~~~~~

Fix this by adding the missing "inline" keyword.

Fixes: 0aa4d016 ("of: mdio: export of_mdiobus_child_is_phy")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

7df2281a

net: phy: aquantia: add suspend / resume ops for AQR105 · 1c93fb45

Madalin Bucur authored Dec 23, 2019

The suspend/resume code for AQR107 works on AQR105 too.
This patch fixes issues with the partner not seeing the link down
when the interface using AQR105 is brought down.

Fixes: bee8259d ("net: phy: add driver for aquantia phy")
Signed-off-by: Madalin Bucur <madalin.bucur@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1c93fb45

dpaa_eth: fix DMA mapping leak · c27569fc

Madalin Bucur authored Dec 23, 2019

On the error path some fragments remain DMA mapped. Adding a fix
that unmaps all the fragments. Rework cleanup path to be simpler.

Fixes: 8151ee88 ("dpaa_eth: use page backed rx buffers")
Signed-off-by: Madalin Bucur <madalin.bucur@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

c27569fc

Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf · ec34c015

David S. Miller authored Dec 26, 2019

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for net:

1) Fix endianness issue in flowtable TCP flags dissector,
   from Arnd Bergmann.

2) Extend flowtable test script with dnat rules, from Florian Westphal.

3) Reject padding in ebtables user entries and validate computed user
   offset, reported by syzbot, from Florian Westphal.

4) Fix endianness in nft_tproxy, from Phil Sutter.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

ec34c015

net/mlxfw: Fix out-of-memory error in mfa2 flash burning · a5bcd72e

Vladyslav Tarasiuk authored Dec 26, 2019

The burning process requires to perform internal allocations of large
chunks of memory. This memory doesn't need to be contiguous and can be
safely allocated by vzalloc() instead of kzalloc(). This patch changes
such allocation to avoid possible out-of-memory failure.

Fixes: 410ed13c ("Add the mlxfw module for Mellanox firmware flash process")
Signed-off-by: Vladyslav Tarasiuk <vladyslavt@mellanox.com>
Reviewed-by: Aya Levin <ayal@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

a5bcd72e

Merge branch 'hsr-fix-several-bugs-in-hsr-module' · 095e90e0

David S. Miller authored Dec 25, 2019

Taehee Yoo says:

====================
hsr: fix several bugs in hsr module

1. The first patch fixes debugfs warning when it's opened when hsr module
is being removed. debugfs file is opened, it tries to hold .owner module,
but it would print warning messages if it couldn't hold .owner module.
In order to avoid the warning message, this patch makes hsr module does
not set .owner. Unsetting .owner is safe because these are protected by
inode_lock().

2. The second patch fixes wrong error handling of hsr_dev_finalize()
a) hsr_dev_finalize() calls debugfs_create_{dir/file} to create debugfs.
it checks NULL pointer but debugfs don't return NULL so it's wrong code.
b) hsr_dev_finalize() calls register_netdevice(). so if it fails after
register_netdevice(), it should call unregister_netdevice().
But it doesn't.
c) debugfs doesn't affect any actual logic of hsr module.
So, the failure of creating of debugfs could be ignored.

3. The third patch adds hsr root debugfs directory.
When hsr interface is created, it creates debugfs directory in
/sys/kernel/debug/<interface name>.
It's a little bit faulty path because if an interface is the same with
another directory name in the same path, it will fail. If hsr root
directory is existing, the possibility of failure of creating debugfs
file will be reduced.

4. The fourth patch adds debugfs rename routine.
debugfs directory name is the same with hsr interface name.
So hsr interface name is changed, debugfs directory name should be
changed too.

5. The fifth patch fixes a race condition in node list add and del.
hsr nodes are protected by RCU and there is no write side lock.
But node insertions and deletions could be being operated concurrently.
So write side locking is needed.

6. The Sixth patch resets network header
Tap routine is enabled, below message will be printed.

[  175.852292][    C3] protocol 88fb is buggy, dev veth0

hsr module doesn't set network header for supervision frame.
But tap routine validates network header.
If network header wasn't set, it resets and warns about it.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

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