We currently have a hand-rolled table with 256 entries and are
using the last byte of the MAC address as the hash. This hash
is obviously very fast, but collisions are easily created and
we waste a lot of space in the common case of just connecting
as a client to an AP where we just have a single station. The
other common case of an AP is also suboptimal due to the size
of the hash table and the ease of causing collisions.

Convert all of this to use rhashtable with jhash, which gives
us the advantage of a far better hash function (with random
perturbation to avoid hash collision attacks) and of course
that the hash table grows and shrinks dynamically with chain
length, improving both cases above.

Use a specialised hash function (using jhash, but with fixed
length) to achieve better compiler optimisation as suggested
by Sergey Ryazanov.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Unlike other places, this function uses name "dev" for what should be
"orig_dev", which might be a bit confusing. So fix this.
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Those are counterparts to nla_put_in_addr and nla_put_in6_addr.
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IP addresses are often stored in netlink attributes. Add generic functions
to do that.

For nla_put_in_addr, it would be nicer to pass struct in_addr but this is
not used universally throughout the kernel, in way too many places __be32 is
used to store IPv4 address.
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In many places, the a6 field is typecasted to struct in6_addr. As the
fields are in union anyway, just add in6_addr type to the union and
get rid of the typecasting.

Modifying the uapi header is okay, the union has still the same size.
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In many places, the a6 field is typecasted to struct in6_addr. As the
fields are in union anyway, just add in6_addr type to the union and get rid
of the typecasting.
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ipv6 code uses a mixture of coding styles. In some instances check for NULL
pointer is done as x != NULL and sometimes as x. x is preferred according to
checkpatch and this patch makes the code consistent by adopting the latter
form.

No changes detected by objdiff.
Signed-off-by: NIan Morris <ipm@chirality.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ipv6 code uses a mixture of coding styles. In some instances check for NULL
pointer is done as x == NULL and sometimes as !x. !x is preferred according to
checkpatch and this patch makes the code consistent by adopting the latter
form.

No changes detected by objdiff.
Signed-off-by: NIan Morris <ipm@chirality.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While fixing a recent issue I noticed that we are doing some unnecessary
work inside the loop for ip_fib_net_exit.  As such I am pulling out the
initialization to NULL for the locally stored fib_local, fib_main, and
fib_default.

In addition I am restoring the original code for flushing the table as
there is no need to split up the fib_table_flush and hlist_del work since
the code for packing the tnodes with multiple key vectors was dropped.
Signed-off-by: NAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fixes the following warning:

 BUG: sleeping function called from invalid context at mm/slub.c:1268
 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u8:0
 INFO: lockdep is turned off.
 CPU: 3 PID: 6 Comm: kworker/u8:0 Tainted: G        W       4.0.0-rc5+ #895
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 Workqueue: netns cleanup_net
  0000000000000006 ffff88011953fa68 ffffffff81a203b6 000000002c3a2c39
  ffff88011952a680 ffff88011953fa98 ffffffff8109daf0 ffff8801186c6aa8
  ffffffff81fbc9e5 00000000000004f4 0000000000000000 ffff88011953fac8
 Call Trace:
  [<ffffffff81a203b6>] dump_stack+0x4c/0x65
  [<ffffffff8109daf0>] ___might_sleep+0x1c3/0x1cb
  [<ffffffff8109db70>] __might_sleep+0x78/0x80
  [<ffffffff8117a60e>] slab_pre_alloc_hook+0x31/0x8f
  [<ffffffff8117d4f6>] __kmalloc+0x69/0x14e
  [<ffffffff818ed0e1>] ? kzalloc.constprop.20+0xe/0x10
  [<ffffffff818ed0e1>] kzalloc.constprop.20+0xe/0x10
  [<ffffffff818ef622>] fib_trie_table+0x27/0x8b
  [<ffffffff818ef6bd>] fib_trie_unmerge+0x37/0x2a6
  [<ffffffff810b06e1>] ? arch_local_irq_save+0x9/0xc
  [<ffffffff818e9793>] fib_unmerge+0x2d/0xb3
  [<ffffffff818f5f56>] fib4_rule_delete+0x1f/0x52
  [<ffffffff817f1c3f>] ? fib_rules_unregister+0x30/0xb2
  [<ffffffff817f1c8b>] fib_rules_unregister+0x7c/0xb2
  [<ffffffff818f64a1>] fib4_rules_exit+0x15/0x18
  [<ffffffff818e8c0a>] ip_fib_net_exit+0x23/0xf2
  [<ffffffff818e91f8>] fib_net_exit+0x32/0x36
  [<ffffffff817c8352>] ops_exit_list+0x45/0x57
  [<ffffffff817c8d3d>] cleanup_net+0x13c/0x1cd
  [<ffffffff8108b05d>] process_one_work+0x255/0x4ad
  [<ffffffff8108af69>] ? process_one_work+0x161/0x4ad
  [<ffffffff8108b4b1>] worker_thread+0x1cd/0x2ab
  [<ffffffff8108b2e4>] ? process_scheduled_works+0x2f/0x2f
  [<ffffffff81090686>] kthread+0xd4/0xdc
  [<ffffffff8109ec8f>] ? local_clock+0x19/0x22
  [<ffffffff810905b2>] ? __kthread_parkme+0x83/0x83
  [<ffffffff81a2c0c8>] ret_from_fork+0x58/0x90
  [<ffffffff810905b2>] ? __kthread_parkme+0x83/0x83

The issue was that as a part of exiting the default rules were being
deleted which resulted in the local trie being unmerged.  By moving the
freeing of the FIB tables up we can avoid the unmerge since there is no
local table left when we call the fib4_rules_exit function.

Fixes: 0ddcf43d ("ipv4: FIB Local/MAIN table collapse")
Reported-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the upcoming fast-xmit patch, changing station state will
build a header cache based on the station's capabilities, and
as the QoS capability (sta.wme) impacts the header, it needs
to be set before.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

These are mandated by IEEE802.11-2012 section 8.5.8.6 and IEEE802.11ac-2013
section 8.5.8.16.
Signed-off-by: NArik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Add VHT support for IBSS. Drivers could activate
this feature by setting NL80211_EXT_FEATURE_VHT_IBSS
flag.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

In case of wide bandwidth (wider than 20MHz) used by IBSS,
scan all channels in chandef to be able to find neighboring
IBSS netwqworks that use the same overall channels but a different
control channel.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

In order to look up the RA station earlier to implement a TX
fastpath, factor out the lookup from ieee80211_build_hdr().
To always have a valid station pointer, also move some of the
checks into the new function.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Indicating just the peer's capability is fairly pointless
if the local device doesn't support it. Make the variable
track both combined, and remove the 'local support' check
in the TX path.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Louis reported that a static checker was complaining that
the 'dst' variable was set (multiple times) but not used.
This is due to a previous commit having removed the usage
(apparently erroneously), so add it back.

Fixes: a344d677 ("mac80211: allow drivers to support NL80211_SCAN_FLAG_RANDOM_ADDR")
Reported-by: NLouis Langholtz <lou_langholtz@me.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This code is written using an anti-pattern called "success handling"
which makes it hard to read, especially if you are used to normal kernel
style.  It should instead be written as a list of directives in a row
with branches for error handling.

(Basically copied from Dan's previous patch for CCM)
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This code is written using an anti-pattern called "success handling"
which makes it hard to read, especially if you are used to normal kernel
style.  It should instead be written as a list of directives in a row
with branches for error handling.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Commit 8ade538b ("mac80111: Add BIP-GMAC-128 and BIP-GMAC-256
ciphers") had the success return in incorrect place before the
crypto_aead_setauthsize() call which practically ended up skipping that
call unconditionally.

The missing call did not actually change any functionality since
GMAC_MIC_LEN (16) is identical to the maxauthsize in gcm(aes) and as
such, the default value used for the authsize parameter.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This will expose in /sys whether the ifname of a device is set by
userspace or generated by the kernel. The latter kind (wlanX, etc)
is not deterministic, so userspace needs to rename these devices
to names that are guaranteed to stay the same between reboots. The
former, however should never be renamed, so userspace needs to be
able to reliably tell the difference.

Similar functionality was introduced for the rtnetlink core in
commit 5517750f ("net: rtnetlink - make create_link take name_assign_type")
Signed-off-by: NTom Gundersen <teg@jklm.no>
Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Cc: Brett Rudley <brudley@broadcom.com>
Cc: Arend van Spriel <arend@broadcom.com>
Cc: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Cc: Hante Meuleman <meuleman@broadcom.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
[reformat changelog to fit 72 cols]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Signed-off-by: NMichael Braun <michael-dev@fami-braun.de>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

If a peer or some local agent (rate control, ...) decides to start
an aggregation session but doesn't support HT (which also implies
QoS), reject it.

This is mostly a corner case as such peers normally won't try to
use block-ack sessions and rate control wouldn't start them, but
technically QoS stations could request it according to the spec.

However, since drivers don't really support such non-HT sessions
it's better to reject them.

Also, while at it, move the tracing for TX sessions earlier so it
captures the error cases as well.
Reviewed-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Seems Broadcom TDLS peers (Nexus 5, Xperia Z3) refuse to allow TDLS
connection when channel-switching is supported but the regulatory
classes IE is missing from the setup request.
Add a chandef to reg-class translation function to cfg80211 and use it
to add the required IE during setup. For now add only the current
regulatory class as supported - it is enough to resolve the
compatibility issue.
Signed-off-by: NArik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Stop scan before authentication or association to make sure
that nothing interferes with connection flow.

Currently mac80211 defers RX auth and assoc packets (among other ones)
until after the scan is complete, so auth during scan is likely to fail
if scan took too much time.
Signed-off-by: NDavid Spinadel <david.spinadel@intel.com>
Reviewed-by: NLuciano Coelho <luciano.coelho@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Pass the initial net-detect delay (NL80211_ATTR_SCHED_SCAN_DELAY)
attribute in the WoWLAN info response.

Additionally, remove a bogus TODO comment.
Signed-off-by: NLuciano Coelho <luciano.coelho@intel.com>
Reviewed-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This can allow the driver to take action based on the reason
of the deauth.
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This can allow the driver to take action based on the
success / failure of the association.
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This can allow the driver to take action based on the
success / failure of the authentication.
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

We will be able to add more events, such as MLME events and
others. The low level driver may be interested in knowing
about these events to dump firmware data upon failures, or
to change parameters in case connection attempts fail etc...
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The rate control locking caused a potential deadlock here due to the
locks being acquired in different orders, so that change cannot yet
be applied. However, there's no fundamental reason for this code to
hold the sta->lock while transmitting frames.

Clearly it's better not to hold the lock for longer periods of time,
which can happen here since we call all the way down to the driver.
Change the code a bit to not hold it while doing that.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

A message sent to a node after a successful name table lookup may still
find that the destination socket has disappeared, because distribution
of name table updates is non-atomic. If so, the message will be rejected
back to the sender with error code TIPC_ERR_NO_PORT. If the source
socket of the message has disappeared in the meantime, the message
should be dropped.

However, in the currrent code, the message will instead be subject to an
unwanted tertiary lookup, because the function tipc_msg_lookup_dest()
doesn't check if there is an error code present in the message before
performing the lookup. In the worst case, the message may now find the
old destination again, and be redirected once more, instead of being
dropped directly as it should be.

A second bug in this function is that the "prev_node" field in the message
is not updated after successful lookup, something that may have
unpredictable consequences.

The problems arising from those bugs occur very infrequently.

The third change in this function; the test on msg_reroute_msg_cnt() is
purely cosmetic, reflecting that the returned value never can be negative.

This commit corrects the two bugs described above.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As there are a number of (especially virtual) devices that don't
need the multiple vlan check, introduce passthru_features_check() for
convenience.
Signed-off-by: NToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To allow drivers to handle the features check for multiple tags,
move the check to ndo_features_check().
As no drivers currently handle multiple tagged TSO, introduce
dflt_features_check() and call it if the driver does not have
ndo_features_check().
Signed-off-by: NToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Separate the two checks for single vlan and multiple vlans in
netif_skb_features().  This allows us to move the check for multiple
vlans to another function later.
Signed-off-by: NToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Stacked vlan devices curretly have few features (GRO, HIGHDMA, LLTX).
Since we have software fallbacks in case the NIC can not handle some
features for multiple vlans, we can add the same features as the lower
vlan devices for stacked vlan devices.

This allows stacked vlan devices to create large (GSO) packets and not to
segment packets. Those packets will be segmented by software on the real
device, or even can be segmented by the NIC once TSO for multiple vlans
becomes enabled by the following patches.

The exception is those related to FCoE, which does not have a software
fallback.
Signed-off-by: NToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

existing TC action 'pedit' can munge any bits of the packet.
Generalize it for use in bpf programs attached as cls_bpf and act_bpf via
bpf_skb_store_bytes() helper function.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Reviewed-by: NJiri Pirko <jiri@resnulli.us>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Provide callbacks for ndo_fdb_add, ndo_fdb_del, and ndo_fdb_dump.
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TIPC node hash node table is protected with rcu lock on read side.
tipc_node_find() is used to look for a node object with node address
through iterating the hash node table. As the entire process of what
tipc_node_find() traverses the table is guarded with rcu read lock,
it's safe for us. However, when callers use the node object returned
by tipc_node_find(), there is no rcu read lock applied. Therefore,
this is absolutely unsafe for callers of tipc_node_find().

Now we introduce a reference counter for node structure. Before
tipc_node_find() returns node object to its caller, it first increases
the reference counter. Accordingly, after its caller used it up,
it decreases the counter again. This can prevent a node being used by
one thread from being freed by another thread.
Reviewed-by: NErik Hugne <erik.hugne@ericsson.com>
Reviewed-by: NJon Maloy <jon.maloy@ericson.com>
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

[   60.988363] ======================================================
[   60.988754] [ INFO: possible circular locking dependency detected ]
[   60.989152] 3.19.0+ #194 Not tainted
[   60.989377] -------------------------------------------------------
[   60.989781] swapper/3/0 is trying to acquire lock:
[   60.990079]  (&(&n_ptr->lock)->rlock){+.-...}, at: [<ffffffffa0006dca>] tipc_link_retransmit+0x1aa/0x240 [tipc]
[   60.990743]
[   60.990743] but task is already holding lock:
[   60.991106]  (&(&bclink->lock)->rlock){+.-...}, at: [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc]
[   60.991738]
[   60.991738] which lock already depends on the new lock.
[   60.991738]
[   60.992174]
[   60.992174] the existing dependency chain (in reverse order) is:
[   60.992174]
-> #1 (&(&bclink->lock)->rlock){+.-...}:
[   60.992174]        [<ffffffff810a9c0c>] lock_acquire+0x9c/0x140
[   60.992174]        [<ffffffff8179c41f>] _raw_spin_lock_bh+0x3f/0x50
[   60.992174]        [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc]
[   60.992174]        [<ffffffffa0000f57>] tipc_bclink_add_node+0x97/0xf0 [tipc]
[   60.992174]        [<ffffffffa0011815>] tipc_node_link_up+0xf5/0x110 [tipc]
[   60.992174]        [<ffffffffa0007783>] link_state_event+0x2b3/0x4f0 [tipc]
[   60.992174]        [<ffffffffa00193c0>] tipc_link_proto_rcv+0x24c/0x418 [tipc]
[   60.992174]        [<ffffffffa0008857>] tipc_rcv+0x827/0xac0 [tipc]
[   60.992174]        [<ffffffffa0002ca3>] tipc_l2_rcv_msg+0x73/0xd0 [tipc]
[   60.992174]        [<ffffffff81646e66>] __netif_receive_skb_core+0x746/0x980
[   60.992174]        [<ffffffff816470c1>] __netif_receive_skb+0x21/0x70
[   60.992174]        [<ffffffff81647295>] netif_receive_skb_internal+0x35/0x130
[   60.992174]        [<ffffffff81648218>] napi_gro_receive+0x158/0x1d0
[   60.992174]        [<ffffffff81559e05>] e1000_clean_rx_irq+0x155/0x490
[   60.992174]        [<ffffffff8155c1b7>] e1000_clean+0x267/0x990
[   60.992174]        [<ffffffff81647b60>] net_rx_action+0x150/0x360
[   60.992174]        [<ffffffff8105ec43>] __do_softirq+0x123/0x360
[   60.992174]        [<ffffffff8105f12e>] irq_exit+0x8e/0xb0
[   60.992174]        [<ffffffff8179f9f5>] do_IRQ+0x65/0x110
[   60.992174]        [<ffffffff8179da6f>] ret_from_intr+0x0/0x13
[   60.992174]        [<ffffffff8100de9f>] arch_cpu_idle+0xf/0x20
[   60.992174]        [<ffffffff8109dfa6>] cpu_startup_entry+0x2f6/0x3f0
[   60.992174]        [<ffffffff81033cda>] start_secondary+0x13a/0x150
[   60.992174]
-> #0 (&(&n_ptr->lock)->rlock){+.-...}:
[   60.992174]        [<ffffffff810a8f7d>] __lock_acquire+0x163d/0x1ca0
[   60.992174]        [<ffffffff810a9c0c>] lock_acquire+0x9c/0x140
[   60.992174]        [<ffffffff8179c41f>] _raw_spin_lock_bh+0x3f/0x50
[   60.992174]        [<ffffffffa0006dca>] tipc_link_retransmit+0x1aa/0x240 [tipc]
[   60.992174]        [<ffffffffa0001e11>] tipc_bclink_rcv+0x611/0x640 [tipc]
[   60.992174]        [<ffffffffa0008646>] tipc_rcv+0x616/0xac0 [tipc]
[   60.992174]        [<ffffffffa0002ca3>] tipc_l2_rcv_msg+0x73/0xd0 [tipc]
[   60.992174]        [<ffffffff81646e66>] __netif_receive_skb_core+0x746/0x980
[   60.992174]        [<ffffffff816470c1>] __netif_receive_skb+0x21/0x70
[   60.992174]        [<ffffffff81647295>] netif_receive_skb_internal+0x35/0x130
[   60.992174]        [<ffffffff81648218>] napi_gro_receive+0x158/0x1d0
[   60.992174]        [<ffffffff81559e05>] e1000_clean_rx_irq+0x155/0x490
[   60.992174]        [<ffffffff8155c1b7>] e1000_clean+0x267/0x990
[   60.992174]        [<ffffffff81647b60>] net_rx_action+0x150/0x360
[   60.992174]        [<ffffffff8105ec43>] __do_softirq+0x123/0x360
[   60.992174]        [<ffffffff8105f12e>] irq_exit+0x8e/0xb0
[   60.992174]        [<ffffffff8179f9f5>] do_IRQ+0x65/0x110
[   60.992174]        [<ffffffff8179da6f>] ret_from_intr+0x0/0x13
[   60.992174]        [<ffffffff8100de9f>] arch_cpu_idle+0xf/0x20
[   60.992174]        [<ffffffff8109dfa6>] cpu_startup_entry+0x2f6/0x3f0
[   60.992174]        [<ffffffff81033cda>] start_secondary+0x13a/0x150
[   60.992174]
[   60.992174] other info that might help us debug this:
[   60.992174]
[   60.992174]  Possible unsafe locking scenario:
[   60.992174]
[   60.992174]        CPU0                    CPU1
[   60.992174]        ----                    ----
[   60.992174]   lock(&(&bclink->lock)->rlock);
[   60.992174]                                lock(&(&n_ptr->lock)->rlock);
[   60.992174]                                lock(&(&bclink->lock)->rlock);
[   60.992174]   lock(&(&n_ptr->lock)->rlock);
[   60.992174]
[   60.992174]  *** DEADLOCK ***
[   60.992174]
[   60.992174] 3 locks held by swapper/3/0:
[   60.992174]  #0:  (rcu_read_lock){......}, at: [<ffffffff81646791>] __netif_receive_skb_core+0x71/0x980
[   60.992174]  #1:  (rcu_read_lock){......}, at: [<ffffffffa0002c35>] tipc_l2_rcv_msg+0x5/0xd0 [tipc]
[   60.992174]  #2:  (&(&bclink->lock)->rlock){+.-...}, at: [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc]
[   60.992174]

The correct the sequence of grabbing n_ptr->lock and bclink->lock
should be that the former is first held and the latter is then taken,
which exactly happened on CPU1. But especially when the retransmission
of broadcast link is failed, bclink->lock is first held in
tipc_bclink_rcv(), and n_ptr->lock is taken in link_retransmit_failure()
called by tipc_link_retransmit() subsequently, which is demonstrated on
CPU0. As a result, deadlock occurs.

If the order of holding the two locks happening on CPU0 is reversed, the
deadlock risk will be relieved. Therefore, the node lock taken in
link_retransmit_failure() originally is moved to tipc_bclink_rcv()
so that it's obtained before bclink lock. But the precondition of
the adjustment of node lock is that responding to bclink reset event
must be moved from tipc_bclink_unlock() to tipc_node_unlock().
Reviewed-by: NErik Hugne <erik.hugne@ericsson.com>
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>