Commits · 4c16d64ea04056f1b1b324ab6916019f6a064114 · nexedi / linux

03 Mar, 2020 3 commits

fib: add missing attribute validation for tun_id · 4c16d64e

Jakub Kicinski authored Mar 02, 2020

Add missing netlink policy entry for FRA_TUN_ID.

Fixes: e7030878 ("fib: Add fib rule match on tunnel id")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4c16d64e

devlink: validate length of region addr/len · ff3b63b8

Jakub Kicinski authored Mar 02, 2020

DEVLINK_ATTR_REGION_CHUNK_ADDR and DEVLINK_ATTR_REGION_CHUNK_LEN
lack entries in the netlink policy. Corresponding nla_get_u64()s
may read beyond the end of the message.

Fixes: 4e54795a ("devlink: Add support for region snapshot read command")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ff3b63b8

devlink: validate length of param values · 8750939b

Jakub Kicinski authored Mar 02, 2020

DEVLINK_ATTR_PARAM_VALUE_DATA may have different types
so it's not checked by the normal netlink policy. Make
sure the attribute length is what we expect.

Fixes: e3b7ca18 ("devlink: Add param set command")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

8750939b

02 Mar, 2020 4 commits

Merge branch 'bnxt_en-2-bug-fixes' · ab124d58

David S. Miller authored Mar 01, 2020

Michael Chan says:

====================
bnxt_en: 2 bug fixes.

This first patch fixes a rare but possible crash in pci_disable_msix()
when the MTU is changed.  The 2nd patch fixes a regression in error
code handling when flashing a file to NVRAM.

Please also queue these for -stable.  Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

ab124d58

bnxt_en: fix error handling when flashing from file · 22630e28

Edwin Peer authored Mar 01, 2020

After bnxt_hwrm_do_send_message() was updated to return standard error
codes in a recent commit, a regression in bnxt_flash_package_from_file()
was introduced. The return value does not properly reflect all
possible firmware errors when calling firmware to flash the package.

Fix it by consolidating all errors in one local variable rc instead
of having 2 variables for different errors.

Fixes: d4f1420d ("bnxt_en: Convert error code in firmware message response to standard code.")
Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

22630e28

bnxt_en: reinitialize IRQs when MTU is modified · a9b952d2

Vasundhara Volam authored Mar 01, 2020

MTU changes may affect the number of IRQs so we must call
bnxt_close_nic()/bnxt_open_nic() with the irq_re_init parameter
set to true.  The reason is that a larger MTU may require
aggregation rings not needed with smaller MTU.  We may not be
able to allocate the required number of aggregation rings and
so we reduce the number of channels which will change the number
of IRQs.  Without this patch, it may crash eventually in
pci_disable_msix() when the IRQs are not properly unwound.

Fixes: c0c050c5 ("bnxt_en: New Broadcom ethernet driver.")
Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

a9b952d2

net: phy: avoid clearing PHY interrupts twice in irq handler · 249bc974

Heiner Kallweit authored Mar 01, 2020

On all PHY drivers that implement did_interrupt() reading the interrupt
status bits clears them. This means we may loose an interrupt that
is triggered between calling did_interrupt() and phy_clear_interrupt().
As part of the fix make it a requirement that did_interrupt() clears
the interrupt.

The Fixes tag refers to the first commit where the patch applies
cleanly.

Fixes: 49644e68 ("net: phy: add callback for custom interrupt handler to struct phy_driver")
Reported-by: Michael Walle <michael@walle.cc>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

249bc974

01 Mar, 2020 6 commits

net: dsa: sja1105: Don't destroy not-yet-created xmit_worker · 52c0d4e3

Vladimir Oltean authored Feb 29, 2020

Fixes the following NULL pointer dereference on PHY connect error path
teardown:

[    2.291010] sja1105 spi0.1: Probed switch chip: SJA1105T
[    2.310044] sja1105 spi0.1: Enabled switch tagging
[    2.314970] fsl-gianfar soc:ethernet@2d90000 eth2: error -19 setting up slave phy
[    2.322463] 8<--- cut here ---
[    2.325497] Unable to handle kernel NULL pointer dereference at virtual address 00000018
[    2.333555] pgd = (ptrval)
[    2.336241] [00000018] *pgd=00000000
[    2.339797] Internal error: Oops: 5 [#1] SMP ARM
[    2.344384] Modules linked in:
[    2.347420] CPU: 1 PID: 64 Comm: kworker/1:1 Not tainted 5.5.0-rc5 #1
[    2.353820] Hardware name: Freescale LS1021A
[    2.358070] Workqueue: events deferred_probe_work_func
[    2.363182] PC is at kthread_destroy_worker+0x4/0x74
[    2.368117] LR is at sja1105_teardown+0x70/0xb4
[    2.372617] pc : [<c036cdd4>]    lr : [<c0b89238>]    psr: 60000013
[    2.378845] sp : eeac3d30  ip : eeab1900  fp : eef45480
[    2.384036] r10: eef4549c  r9 : 00000001  r8 : 00000000
[    2.389227] r7 : eef527c0  r6 : 00000034  r5 : ed8ddd0c  r4 : ed8ddc40
[    2.395714] r3 : 00000000  r2 : 00000000  r1 : eef4549c  r0 : 00000000
[    2.402204] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[    2.409297] Control: 10c5387d  Table: 8020406a  DAC: 00000051
[    2.415008] Process kworker/1:1 (pid: 64, stack limit = 0x(ptrval))
[    2.421237] Stack: (0xeeac3d30 to 0xeeac4000)
[    2.612635] [<c036cdd4>] (kthread_destroy_worker) from [<c0b89238>] (sja1105_teardown+0x70/0xb4)
[    2.621379] [<c0b89238>] (sja1105_teardown) from [<c10717fc>] (dsa_switch_teardown.part.1+0x48/0x74)
[    2.630467] [<c10717fc>] (dsa_switch_teardown.part.1) from [<c1072438>] (dsa_register_switch+0x8b0/0xbf4)
[    2.639984] [<c1072438>] (dsa_register_switch) from [<c0b89c30>] (sja1105_probe+0x2ac/0x464)
[    2.648378] [<c0b89c30>] (sja1105_probe) from [<c0b11a5c>] (spi_drv_probe+0x7c/0xa0)
[    2.656081] [<c0b11a5c>] (spi_drv_probe) from [<c0a26ab8>] (really_probe+0x208/0x480)
[    2.663871] [<c0a26ab8>] (really_probe) from [<c0a26f0c>] (driver_probe_device+0x78/0x1c4)
[    2.672093] [<c0a26f0c>] (driver_probe_device) from [<c0a24c48>] (bus_for_each_drv+0x80/0xc4)
[    2.680574] [<c0a24c48>] (bus_for_each_drv) from [<c0a26810>] (__device_attach+0xd0/0x168)
[    2.688794] [<c0a26810>] (__device_attach) from [<c0a259d8>] (bus_probe_device+0x84/0x8c)
[    2.696927] [<c0a259d8>] (bus_probe_device) from [<c0a25f24>] (deferred_probe_work_func+0x84/0xc4)
[    2.705842] [<c0a25f24>] (deferred_probe_work_func) from [<c03667b0>] (process_one_work+0x22c/0x560)
[    2.714926] [<c03667b0>] (process_one_work) from [<c0366d8c>] (worker_thread+0x2a8/0x5d4)
[    2.723059] [<c0366d8c>] (worker_thread) from [<c036cf94>] (kthread+0x150/0x154)
[    2.730416] [<c036cf94>] (kthread) from [<c03010e8>] (ret_from_fork+0x14/0x2c)

Checking for NULL pointer is correct because the per-port xmit kernel
threads are created in sja1105_probe immediately after calling
dsa_register_switch.

Fixes: a68578c2 ("net: dsa: Make deferred_xmit private to sja1105")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

52c0d4e3

net/ipv6: use configured metric when add peer route · 07758eb9

Hangbin Liu authored Feb 29, 2020

When we add peer address with metric configured, IPv4 could set the dest
metric correctly, but IPv6 do not. e.g.

]# ip addr add 192.0.2.1 peer 192.0.2.2/32 dev eth1 metric 20
]# ip route show dev eth1
192.0.2.2 proto kernel scope link src 192.0.2.1 metric 20
]# ip addr add 2001:db8::1 peer 2001:db8::2/128 dev eth1 metric 20
]# ip -6 route show dev eth1
2001:db8::1 proto kernel metric 20 pref medium
2001:db8::2 proto kernel metric 256 pref medium

Fix this by using configured metric instead of default one.
Reported-by: Jianlin Shi <jishi@redhat.com>
Fixes: 8308f3ff ("net/ipv6: Add support for specifying metric of connected routes")
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

07758eb9

net: dsa: mv88e6xxx: fix lockup on warm boot · 0395823b

Russell King authored Feb 28, 2020

If the switch is not hardware reset on a warm boot, interrupts can be
left enabled, and possibly pending. This will cause us to enter an
infinite loop trying to service an interrupt we are unable to handle,
thereby preventing the kernel from booting.

Ensure that the global 2 interrupt sources are disabled before we claim
the parent interrupt.

Observed on the ZII development revision B and C platforms with
reworked serdes support, and using reboot -f to reboot the platform.

Fixes: dc30c35b ("net: dsa: mv88e6xxx: Implement interrupt support.")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

0395823b

atm: nicstar: fix if-statement empty body warning · 8a171c5c

Randy Dunlap authored Feb 27, 2020

When debugging via PRINTK() is not enabled, make the PRINTK()
macro be an empty do-while block.

Thix fixes a gcc warning when -Wextra is set:
../drivers/atm/nicstar.c:1819:23: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body]

I have verified that there is no object code change (with gcc 7.5.0).
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Chas Williams <3chas3@gmail.com>
Cc: linux-atm-general@lists.sourceforge.net
Cc: netdev@vger.kernel.org
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

8a171c5c

netlink: Use netlink header as base to calculate bad attribute offset · 84b32680

Pablo Neira Ayuso authored Feb 26, 2020

Userspace might send a batch that is composed of several netlink
messages. The netlink_ack() function must use the pointer to the netlink
header as base to calculate the bad attribute offset.

Fixes: 2d4bc933 ("netlink: extended ACK reporting")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

84b32680

r8152: check disconnect status after long sleep · d64c7a08

You-Sheng Yang authored Feb 26, 2020

Dell USB Type C docking WD19/WD19DC attaches additional peripherals as:

  /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
      |__ Port 1: Dev 11, If 0, Class=Hub, Driver=hub/4p, 5000M
          |__ Port 3: Dev 12, If 0, Class=Hub, Driver=hub/4p, 5000M
          |__ Port 4: Dev 13, If 0, Class=Vendor Specific Class,
              Driver=r8152, 5000M

where usb 2-1-3 is a hub connecting all USB Type-A/C ports on the dock.

When hotplugging such dock with additional usb devices already attached on
it, the probing process may reset usb 2.1 port, therefore r8152 ethernet
device is also reset. However, during r8152 device init there are several
for-loops that, when it's unable to retrieve hardware registers due to
being disconnected from USB, may take up to 14 seconds each in practice,
and that has to be completed before USB may re-enumerate devices on the
bus. As a result, devices attached to the dock will only be available
after nearly 1 minute after the dock was plugged in:

  [ 216.388290] [250] r8152 2-1.4:1.0: usb_probe_interface
  [ 216.388292] [250] r8152 2-1.4:1.0: usb_probe_interface - got id
  [ 258.830410] r8152 2-1.4:1.0 (unnamed net_device) (uninitialized): PHY not ready
  [ 258.830460] r8152 2-1.4:1.0 (unnamed net_device) (uninitialized): Invalid header when reading pass-thru MAC addr
  [ 258.830464] r8152 2-1.4:1.0 (unnamed net_device) (uninitialized): Get ether addr fail

This happens in, for example, r8153_init:

  static int generic_ocp_read(struct r8152 *tp, u16 index, u16 size,
			    void *data, u16 type)
  {
    if (test_bit(RTL8152_UNPLUG, &tp->flags))
      return -ENODEV;
    ...
  }

  static u16 ocp_read_word(struct r8152 *tp, u16 type, u16 index)
  {
    u32 data;
    ...
    generic_ocp_read(tp, index, sizeof(tmp), &tmp, type | byen);

    data = __le32_to_cpu(tmp);
    ...
    return (u16)data;
  }

  static void r8153_init(struct r8152 *tp)
  {
    ...
    if (test_bit(RTL8152_UNPLUG, &tp->flags))
      return;

    for (i = 0; i < 500; i++) {
      if (ocp_read_word(tp, MCU_TYPE_PLA, PLA_BOOT_CTRL) &
          AUTOLOAD_DONE)
        break;
      msleep(20);
    }
    ...
  }

Since ocp_read_word() doesn't check the return status of
generic_ocp_read(), and the only exit condition for the loop is to have
a match in the returned value, such loops will only ends after exceeding
its maximum runs when the device has been marked as disconnected, which
takes 500 * 20ms = 10 seconds in theory, 14 in practice.

To solve this long latency another test to RTL8152_UNPLUG flag should be
added after those 20ms sleep to skip unnecessary loops, so that the device
probe can complete early and proceed to parent port reset/reprobe process.

This can be reproduced on all kernel versions up to latest v5.6-rc2, but
after v5.5-rc7 the reproduce rate is dramatically lowered to 1/30 or less
while it was around 1/2.
Signed-off-by: You-Sheng Yang <vicamo.yang@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

d64c7a08

28 Feb, 2020 1 commit

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net · 7058b837

Linus Torvalds authored Feb 27, 2020

Pull networking fixes from David Miller:

 1) Fix leak in nl80211 AP start where we leak the ACL memory, from
    Johannes Berg.

 2) Fix double mutex unlock in mac80211, from Andrei Otcheretianski.

 3) Fix RCU stall in ipset, from Jozsef Kadlecsik.

 4) Fix devlink locking in devlink_dpipe_table_register, from Madhuparna
    Bhowmik.

 5) Fix race causing TX hang in ll_temac, from Esben Haabendal.

 6) Stale eth hdr pointer in br_dev_xmit(), from Nikolay Aleksandrov.

 7) Fix TX hash calculation bounds checking wrt. tc rules, from Amritha
    Nambiar.

 8) Size netlink responses properly in schedule action code to take into
    consideration TCA_ACT_FLAGS. From Jiri Pirko.

 9) Fix firmware paths for mscc PHY driver, from Antoine Tenart.

10) Don't register stmmac notifier multiple times, from Aaro Koskinen.

11) Various rmnet bug fixes, from Taehee Yoo.

12) Fix vsock deadlock in vsock transport release, from Stefano
    Garzarella.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (61 commits)
  net: dsa: mv88e6xxx: Fix masking of egress port
  mlxsw: pci: Wait longer before accessing the device after reset
  sfc: fix timestamp reconstruction at 16-bit rollover points
  vsock: fix potential deadlock in transport->release()
  unix: It's CONFIG_PROC_FS not CONFIG_PROCFS
  net: rmnet: fix packet forwarding in rmnet bridge mode
  net: rmnet: fix bridge mode bugs
  net: rmnet: use upper/lower device infrastructure
  net: rmnet: do not allow to change mux id if mux id is duplicated
  net: rmnet: remove rcu_read_lock in rmnet_force_unassociate_device()
  net: rmnet: fix suspicious RCU usage
  net: rmnet: fix NULL pointer dereference in rmnet_changelink()
  net: rmnet: fix NULL pointer dereference in rmnet_newlink()
  net: phy: marvell: don't interpret PHY status unless resolved
  mlx5: register lag notifier for init network namespace only
  unix: define and set show_fdinfo only if procfs is enabled
  hinic: fix a bug of rss configuration
  hinic: fix a bug of setting hw_ioctxt
  hinic: fix a irq affinity bug
  net/smc: check for valid ib_client_data
  ...

7058b837

27 Feb, 2020 26 commits

net: dsa: mv88e6xxx: Fix masking of egress port · 3ee339eb

Andrew Lunn authored Feb 27, 2020

Add missing ~ to the usage of the mask.
Reported-by: Kevin Benson <Kevin.Benson@zii.aero>
Reported-by: Chris Healy <Chris.Healy@zii.aero>
Fixes: 5c74c54c ("net: dsa: mv88e6xxx: Split monitor port configuration")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

3ee339eb

mlxsw: pci: Wait longer before accessing the device after reset · ac004e84

Amit Cohen authored Feb 27, 2020

During initialization the driver issues a reset to the device and waits
for 100ms before checking if the firmware is ready. The waiting is
necessary because before that the device is irresponsive and the first
read can result in a completion timeout.

While 100ms is sufficient for Spectrum-1 and Spectrum-2, it is
insufficient for Spectrum-3.

Fix this by increasing the timeout to 200ms.

Fixes: da382875 ("mlxsw: spectrum: Extend to support Spectrum-3 ASIC")
Signed-off-by: Amit Cohen <amitc@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ac004e84

sfc: fix timestamp reconstruction at 16-bit rollover points · 23797b98

Alex Maftei (amaftei) authored Feb 26, 2020

We can't just use the top bits of the last sync event as they could be
off-by-one every 65,536 seconds, giving an error in reconstruction of
65,536 seconds.

This patch uses the difference in the bottom 16 bits (mod 2^16) to
calculate an offset that needs to be applied to the last sync event to
get to the current time.
Signed-off-by: Alexandru-Mihai Maftei <amaftei@solarflare.com>
Acked-by: Martin Habets <mhabets@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

23797b98

vsock: fix potential deadlock in transport->release() · 3f74957f

Stefano Garzarella authored Feb 26, 2020

Some transports (hyperv, virtio) acquire the sock lock during the
.release() callback.

In the vsock_stream_connect() we call vsock_assign_transport(); if
the socket was previously assigned to another transport, the
vsk->transport->release() is called, but the sock lock is already
held in the vsock_stream_connect(), causing a deadlock reported by
syzbot:

    INFO: task syz-executor280:9768 blocked for more than 143 seconds.
      Not tainted 5.6.0-rc1-syzkaller #0
    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    syz-executor280 D27912  9768   9766 0x00000000
    Call Trace:
     context_switch kernel/sched/core.c:3386 [inline]
     __schedule+0x934/0x1f90 kernel/sched/core.c:4082
     schedule+0xdc/0x2b0 kernel/sched/core.c:4156
     __lock_sock+0x165/0x290 net/core/sock.c:2413
     lock_sock_nested+0xfe/0x120 net/core/sock.c:2938
     virtio_transport_release+0xc4/0xd60 net/vmw_vsock/virtio_transport_common.c:832
     vsock_assign_transport+0xf3/0x3b0 net/vmw_vsock/af_vsock.c:454
     vsock_stream_connect+0x2b3/0xc70 net/vmw_vsock/af_vsock.c:1288
     __sys_connect_file+0x161/0x1c0 net/socket.c:1857
     __sys_connect+0x174/0x1b0 net/socket.c:1874
     __do_sys_connect net/socket.c:1885 [inline]
     __se_sys_connect net/socket.c:1882 [inline]
     __x64_sys_connect+0x73/0xb0 net/socket.c:1882
     do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
     entry_SYSCALL_64_after_hwframe+0x49/0xbe

To avoid this issue, this patch remove the lock acquiring in the
.release() callback of hyperv and virtio transports, and it holds
the lock when we call vsk->transport->release() in the vsock core.

Reported-by: syzbot+731710996d79d0d58fbc@syzkaller.appspotmail.com
Fixes: 408624af ("vsock: use local transport when it is loaded")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3f74957f

unix: It's CONFIG_PROC_FS not CONFIG_PROCFS · 5c05a164

David S. Miller authored Feb 27, 2020

Fixes: 3a12500e ("unix: define and set show_fdinfo only if procfs is enabled")
Signed-off-by: David S. Miller <davem@davemloft.net>

5c05a164

Merge branch 'net-rmnet-fix-several-bugs' · 795c03a5

David S. Miller authored Feb 27, 2020

Taehee Yoo says:

====================
net: rmnet: fix several bugs

This patchset is to fix several bugs in RMNET module.

1. The first patch fixes NULL-ptr-deref in rmnet_newlink().
When rmnet interface is being created, it uses IFLA_LINK
without checking NULL.
So, if userspace doesn't set IFLA_LINK, panic will occur.
In this patch, checking NULL pointer code is added.

2. The second patch fixes NULL-ptr-deref in rmnet_changelink().
To get real device in rmnet_changelink(), it uses IFLA_LINK.
But, IFLA_LINK should not be used in rmnet_changelink().

3. The third patch fixes suspicious RCU usage in rmnet_get_port().
rmnet_get_port() uses rcu_dereference_rtnl().
But, rmnet_get_port() is used by datapath.
So, rcu_dereference_bh() should be used instead of rcu_dereference_rtnl().

4. The fourth patch fixes suspicious RCU usage in
rmnet_force_unassociate_device().
RCU critical section should not be scheduled.
But, unregister_netdevice_queue() in the rmnet_force_unassociate_device()
would be scheduled.
So, the RCU warning occurs.
In this patch, the rcu_read_lock() in the rmnet_force_unassociate_device()
is removed because it's unnecessary.

5. The fifth patch fixes duplicate MUX ID case.
RMNET MUX ID is unique.
So, rmnet interface isn't allowed to be created, which have
a duplicate MUX ID.
But, only rmnet_newlink() checks this condition, rmnet_changelink()
doesn't check this.
So, duplicate MUX ID case would happen.

6. The sixth patch fixes upper/lower interface relationship problems.
When IFLA_LINK is used, the upper/lower infrastructure should be used.
Because it checks the maximum depth of upper/lower interfaces and it also
checks circular interface relationship, etc.
In this patch, netdev_upper_dev_link() is used.

7. The seventh patch fixes bridge related problems.
a) ->ndo_del_slave() doesn't work.
b) It couldn't detect circular upper/lower interface relationship.
c) It couldn't prevent stack overflow because of too deep depth
of upper/lower interface
d) It doesn't check the number of lower interfaces.
e) Panics because of several reasons.
These problems are actually the same problem.
So, this patch fixes these problems.

8. The eighth patch fixes packet forwarding issue in bridge mode
Packet forwarding is not working in rmnet bridge mode.
Because when a packet is forwarded, skb_push() for an ethernet header
is needed. But it doesn't call skb_push().
So, the ethernet header will be lost.

Change log:
 - update commit logs.
 - drop two patches in this patchset because of wrong target branch.
   - ("net: rmnet: add missing module alias")
   - ("net: rmnet: print error message when command fails")
 - remove unneessary rcu_read_lock() in the third patch.
 - use rcu_dereference_bh() instead of rcu_dereference in third patch.
 - do not allow to add a bridge device if rmnet interface is already
   bridge mode in the seventh patch.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

795c03a5