linux.git/net/core/dev.c, branch v3.15-rc2

vlan: Fix lockdep warning when vlan dev handle notification

2014-04-18T21:48:30+00:00

When I open the LOCKDEP config and run these steps:

modprobe 8021q
vconfig add eth2 20
vconfig add eth2.20 30
ifconfig eth2 xx.xx.xx.xx

then the Call Trace happened:

[32524.386288] =============================================
[32524.386293] [ INFO: possible recursive locking detected ]
[32524.386298] 3.14.0-rc2-0.7-default+ #35 Tainted: G           O
[32524.386302] ---------------------------------------------
[32524.386306] ifconfig/3103 is trying to acquire lock:
[32524.386310]  (&vlan_netdev_addr_lock_key/1){+.....}, at: [] dev_mc_sync+0x64/0xb0
[32524.386326]
[32524.386326] but task is already holding lock:
[32524.386330]  (&vlan_netdev_addr_lock_key/1){+.....}, at: [] dev_set_rx_mode+0x23/0x40
[32524.386341]
[32524.386341] other info that might help us debug this:
[32524.386345]  Possible unsafe locking scenario:
[32524.386345]
[32524.386350]        CPU0
[32524.386352]        ----
[32524.386354]   lock(&vlan_netdev_addr_lock_key/1);
[32524.386359]   lock(&vlan_netdev_addr_lock_key/1);
[32524.386364]
[32524.386364]  *** DEADLOCK ***
[32524.386364]
[32524.386368]  May be due to missing lock nesting notation
[32524.386368]
[32524.386373] 2 locks held by ifconfig/3103:
[32524.386376]  #0:  (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x12/0x20
[32524.386387]  #1:  (&vlan_netdev_addr_lock_key/1){+.....}, at: [] dev_set_rx_mode+0x23/0x40
[32524.386398]
[32524.386398] stack backtrace:
[32524.386403] CPU: 1 PID: 3103 Comm: ifconfig Tainted: G           O 3.14.0-rc2-0.7-default+ #35
[32524.386409] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[32524.386414]  ffffffff81ffae40 ffff8800d9625ae8 ffffffff814f68a2 ffff8800d9625bc8
[32524.386421]  ffffffff810a35fb ffff8800d8a8d9d0 00000000d9625b28 ffff8800d8a8e5d0
[32524.386428]  000003cc00000000 0000000000000002 ffff8800d8a8e5f8 0000000000000000
[32524.386435] Call Trace:
[32524.386441]  [] dump_stack+0x6a/0x78
[32524.386448]  [] __lock_acquire+0x7ab/0x1940
[32524.386454]  [] ? __lock_acquire+0x3ea/0x1940
[32524.386459]  [] lock_acquire+0xe4/0x110
[32524.386464]  [] ? dev_mc_sync+0x64/0xb0
[32524.386471]  [] _raw_spin_lock_nested+0x2a/0x40
[32524.386476]  [] ? dev_mc_sync+0x64/0xb0
[32524.386481]  [] dev_mc_sync+0x64/0xb0
[32524.386489]  [] vlan_dev_set_rx_mode+0x2b/0x50 [8021q]
[32524.386495]  [] __dev_set_rx_mode+0x5f/0xb0
[32524.386500]  [] dev_set_rx_mode+0x2b/0x40
[32524.386506]  [] __dev_open+0xef/0x150
[32524.386511]  [] __dev_change_flags+0xa7/0x190
[32524.386516]  [] dev_change_flags+0x32/0x80
[32524.386524]  [] devinet_ioctl+0x7d6/0x830
[32524.386532]  [] ? dev_ioctl+0x34b/0x660
[32524.386540]  [] inet_ioctl+0x80/0xa0
[32524.386550]  [] sock_do_ioctl+0x2d/0x60
[32524.386558]  [] sock_ioctl+0x82/0x2a0
[32524.386568]  [] do_vfs_ioctl+0x93/0x590
[32524.386578]  [] ? rcu_read_lock_held+0x45/0x50
[32524.386586]  [] ? __fget_light+0x105/0x110
[32524.386594]  [] SyS_ioctl+0x91/0xb0
[32524.386604]  [] system_call_fastpath+0x16/0x1b

========================================================================

The reason is that all of the addr_lock_key for vlan dev have the same class,
so if we change the status for vlan dev, the vlan dev and its real dev will
hold the same class of addr_lock_key together, so the warning happened.

we should distinguish the lock depth for vlan dev and its real dev.

v1->v2: Convert the vlan_netdev_addr_lock_key to an array of eight elements, which
	could support to add 8 vlan id on a same vlan dev, I think it is enough for current
	scene, because a netdev's name is limited to IFNAMSIZ which could not hold 8 vlan id,
	and the vlan dev would not meet the same class key with its real dev.

	The new function vlan_dev_get_lockdep_subkey() will return the subkey and make the vlan
	dev could get a suitable class key.

v2->v3: According David's suggestion, I use the subclass to distinguish the lock key for vlan dev
	and its real dev, but it make no sense, because the difference for subclass in the
	lock_class_key doesn't mean that the difference class for lock_key, so I use lock_depth
	to distinguish the different depth for every vlan dev, the same depth of the vlan dev
	could have the same lock_class_key, I import the MAX_LOCK_DEPTH from the include/linux/sched.h,
	I think it is enough here, the lockdep should never exceed that value.

v3->v4: Add a huge array of locking keys will waste static kernel memory and is not a appropriate method,
	we could use _nested() variants to fix the problem, calculate the depth for every vlan dev,
	and use the depth as the subclass for addr_lock_key.

Signed-off-by: Ding Tianhong 
Signed-off-by: David S. Miller

net: Start with correct mac_len in skb_network_protocol

2014-04-14T22:58:58+00:00

Sometimes, when the packet arrives at skb_mac_gso_segment()
its skb->mac_len already accounts for some of the mac lenght
headers in the packet.  This seems to happen when forwarding
through and OpenSSL tunnel.

When we start looking for any vlan headers in skb_network_protocol()
we seem to ignore any of the already known mac headers and start
with an ETH_HLEN.  This results in an incorrect offset, dropped
TSO frames and general slowness of the connection.

We can start counting from the known skb->mac_len
and return at least that much if all mac level headers
are known and accounted for.

Fixes: 53d6471cef17262d3ad1c7ce8982a234244f68ec (net: Account for all vlan headers in skb_mac_gso_segment)
CC: Eric Dumazet 
CC: Daniel Borkman 
Tested-by: Martin Filip 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

netdev: remove potentially harmful checks

2014-04-07T19:52:07+00:00

Currently we're checking a variable for != NULL after actually
dereferencing it, in netdev_lower_get_next_private*().

It's counter-intuitive at best, and can lead to faulty usage (as it implies
that the variable can be NULL), so fix it by removing the useless checks.

Reported-by: Daniel Borkmann 
CC: "David S. Miller" 
CC: Eric Dumazet 
CC: Nicolas Dichtel 
CC: Jiri Pirko 
CC: stephen hemminger 
CC: Jerry Chu 
Signed-off-by: Veaceslav Falico 
Signed-off-by: David S. Miller

net-gro: reset skb->truesize in napi_reuse_skb()

2014-04-03T20:17:52+00:00

Recycling skb always had been very tough...

This time it appears GRO layer can accumulate skb->truesize
adjustments made by drivers when they attach a fragment to skb.

skb_gro_receive() can only subtract from skb->truesize the used part
of a fragment.

I spotted this problem seeing TcpExtPruneCalled and
TcpExtTCPRcvCollapsed that were unexpected with a recent kernel, where
TCP receive window should be sized properly to accept traffic coming
from a driver not overshooting skb->truesize.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: add busy_poll device feature

2014-04-03T18:31:34+00:00

Currently there is no way how to find out if a device supports busy
polling. So add a feature and make it dependent on ndo_busy_poll
existence.

Signed-off-by: Jiri Pirko 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

2014-04-03T03:53:45+00:00

Pull networking updates from David Miller:
 "Here is my initial pull request for the networking subsystem during
  this merge window:

   1) Support for ESN in AH (RFC 4302) from Fan Du.

   2) Add full kernel doc for ethtool command structures, from Ben
      Hutchings.

   3) Add BCM7xxx PHY driver, from Florian Fainelli.

   4) Export computed TCP rate information in netlink socket dumps, from
      Eric Dumazet.

   5) Allow IPSEC SA to be dumped partially using a filter, from Nicolas
      Dichtel.

   6) Convert many drivers to pci_enable_msix_range(), from Alexander
      Gordeev.

   7) Record SKB timestamps more efficiently, from Eric Dumazet.

   8) Switch to microsecond resolution for TCP round trip times, also
      from Eric Dumazet.

   9) Clean up and fix 6lowpan fragmentation handling by making use of
      the existing inet_frag api for it's implementation.

  10) Add TX grant mapping to xen-netback driver, from Zoltan Kiss.

  11) Auto size SKB lengths when composing netlink messages based upon
      past message sizes used, from Eric Dumazet.

  12) qdisc dumps can take a long time, add a cond_resched(), From Eric
      Dumazet.

  13) Sanitize netpoll core and drivers wrt.  SKB handling semantics.
      Get rid of never-used-in-tree netpoll RX handling.  From Eric W
      Biederman.

  14) Support inter-address-family and namespace changing in VTI tunnel
      driver(s).  From Steffen Klassert.

  15) Add Altera TSE driver, from Vince Bridgers.

  16) Optimizing csum_replace2() so that it doesn't adjust the checksum
      by checksumming the entire header, from Eric Dumazet.

  17) Expand BPF internal implementation for faster interpreting, more
      direct translations into JIT'd code, and much cleaner uses of BPF
      filtering in non-socket ocntexts.  From Daniel Borkmann and Alexei
      Starovoitov"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1976 commits)
  netpoll: Use skb_irq_freeable to make zap_completion_queue safe.
  net: Add a test to see if a skb is freeable in irq context
  qlcnic: Fix build failure due to undefined reference to `vxlan_get_rx_port'
  net: ptp: move PTP classifier in its own file
  net: sxgbe: make "core_ops" static
  net: sxgbe: fix logical vs bitwise operation
  net: sxgbe: sxgbe_mdio_register() frees the bus
  Call efx_set_channels() before efx->type->dimension_resources()
  xen-netback: disable rogue vif in kthread context
  net/mlx4: Set proper build dependancy with vxlan
  be2net: fix build dependency on VxLAN
  mac802154: make csma/cca parameters per-wpan
  mac802154: allow only one WPAN to be up at any given time
  net: filter: minor: fix kdoc in __sk_run_filter
  netlink: don't compare the nul-termination in nla_strcmp
  can: c_can: Avoid led toggling for every packet.
  can: c_can: Simplify TX interrupt cleanup
  can: c_can: Store dlc private
  can: c_can: Reduce register access
  can: c_can: Make the code readable
  ...

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2014-04-02T23:23:38+00:00

Pull trivial tree updates from Jiri Kosina:
 "Usual rocket science -- mostly documentation and comment updates"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
  sparse: fix comment
  doc: fix double words
  isdn: capi: fix "CAPI_VERSION" comment
  doc: DocBook: Fix typos in xml and template file
  Bluetooth: add module name for btwilink
  driver core: unexport static function create_syslog_header
  mmc: core: typo fix in printk specifier
  ARM: spear: clean up editing mistake
  net-sysfs: fix comment typo 'CONFIG_SYFS'
  doc: Insert MODULE_ in module-signing macros
  Documentation: update URL to hfsplus Technote 1150
  gpio: update path to documentation
  ixgbe: Fix format string in ixgbe_fcoe.
  Kconfig: Remove useless "default N" lines
  user_namespace.c: Remove duplicated word in comment
  CREDITS: fix formatting
  treewide: Fix typo in Documentation/DocBook
  mm: Fix warning on make htmldocs caused by slab.c
  ata: ata-samsung_cf: cleanup in header file
  idr: remove unused prototype of idr_free()

Merge branch 'for-3.15/core' of git://git.kernel.dk/linux-block

2014-04-02T02:19:15+00:00

Pull core block layer updates from Jens Axboe:
 "This is the pull request for the core block IO bits for the 3.15
  kernel.  It's a smaller round this time, it contains:

   - Various little blk-mq fixes and additions from Christoph and
     myself.

   - Cleanup of the IPI usage from the block layer, and associated
     helper code.  From Frederic Weisbecker and Jan Kara.

   - Duplicate code cleanup in bio-integrity from Gu Zheng.  This will
     give you a merge conflict, but that should be easy to resolve.

   - blk-mq notify spinlock fix for RT from Mike Galbraith.

   - A blktrace partial accounting bug fix from Roman Pen.

   - Missing REQ_SYNC detection fix for blk-mq from Shaohua Li"

* 'for-3.15/core' of git://git.kernel.dk/linux-block: (25 commits)
  blk-mq: add REQ_SYNC early
  rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlock
  blk-mq: support partial I/O completions
  blk-mq: merge blk_mq_insert_request and blk_mq_run_request
  blk-mq: remove blk_mq_alloc_rq
  blk-mq: don't dump CPU -> hw queue map on driver load
  blk-mq: fix wrong usage of hctx->state vs hctx->flags
  blk-mq: allow blk_mq_init_commands() to return failure
  block: remove old blk_iopoll_enabled variable
  blktrace: fix accounting of partially completed requests
  smp: Rename __smp_call_function_single() to smp_call_function_single_async()
  smp: Remove wait argument from __smp_call_function_single()
  watchdog: Simplify a little the IPI call
  smp: Move __smp_call_function_single() below its safe version
  smp: Consolidate the various smp_call_function_single() declensions
  smp: Teach __smp_call_function_single() to check for offline cpus
  smp: Remove unused list_head from csd
  smp: Iterate functions through llist_for_each_entry_safe()
  block: Stop abusing rq->csd.list in blk-softirq
  block: Remove useless IPI struct initialization
  ...

net-gro: restore frag0 optimization

2014-03-31T20:26:40+00:00

Main difference between napi_frags_skb() and napi_gro_receive() is that
the later is called while ethernet header was already pulled by the NIC
driver (eth_type_trans() was called before napi_gro_receive())

Jerry Chu in commit 299603e8370a ("net-gro: Prepare GRO stack for the
upcoming tunneling support") tried to remove this difference by calling
eth_type_trans() from napi_frags_skb() instead of doing this later from
napi_frags_finish()

Goal was that napi_gro_complete() could call
ptype->callbacks.gro_complete(skb, 0)  (offset of first network header =
0)

Also, xxx_gro_receive() handlers all use off = skb_gro_offset(skb) to
point to their own header, for the current skb and ones held in gro_list

Problem is this cleanup work defeated the frag0 optimization:
It turns out the consecutive pskb_may_pull() calls are too expensive.

This patch brings back the frag0 stuff in napi_frags_skb().

As all skb have their mac header in skb head, we no longer need
skb_gro_mac_header()

Reported-by: Michal Schmidt 
Fixes: 299603e8370a ("net-gro: Prepare GRO stack for the upcoming tunneling support")
Signed-off-by: Eric Dumazet 
Cc: Jerry Chu 
Signed-off-by: David S. Miller

net: Allow modules to use is_skb_forwardable

2014-03-31T20:04:04+00:00

Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller