New tracepoint trace_tcp_send_reset is added and called from
tcp_v4_send_reset(), tcp_v6_send_reset() and tcp_send_active_reset().
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use BUG_ON instead of if condition followed by BUG in do_setlink.

This issue was detected with the help of Coccinelle.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When syzkaller team brought us a C repro for the crash [1] that
had been reported many times in the past, I finally could find
the root cause.

If FlowLabel info is merged by fl6_merge_options(), we leave
part of the opt_space storage provided by udp/raw/l2tp with random value
in opt_space.tot_len, unless a control message was provided at sendmsg()
time.

Then ip6_setup_cork() would use this random value to perform a kzalloc()
call. Undefined behavior and crashes.

Fix is to properly set tot_len in fl6_merge_options()

At the same time, we can also avoid consuming memory and cpu cycles
to clear it, if every option is copied via a kmemdup(). This is the
change in ip6_setup_cork().

[1]
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 6613 Comm: syz-executor0 Not tainted 4.14.0-rc4+ #127
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cb64a100 task.stack: ffff8801cc350000
RIP: 0010:ip6_setup_cork+0x274/0x15c0 net/ipv6/ip6_output.c:1168
RSP: 0018:ffff8801cc357550 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: ffff8801cc357748 RCX: 0000000000000010
RDX: 0000000000000002 RSI: ffffffff842bd1d9 RDI: 0000000000000014
RBP: ffff8801cc357620 R08: ffff8801cb17f380 R09: ffff8801cc357b10
R10: ffff8801cb64a100 R11: 0000000000000000 R12: ffff8801cc357ab0
R13: ffff8801cc357b10 R14: 0000000000000000 R15: ffff8801c3bbf0c0
FS:  00007f9c5c459700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020324000 CR3: 00000001d1cf2000 CR4: 00000000001406f0
DR0: 0000000020001010 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 ip6_make_skb+0x282/0x530 net/ipv6/ip6_output.c:1729
 udpv6_sendmsg+0x2769/0x3380 net/ipv6/udp.c:1340
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:762
 sock_sendmsg_nosec net/socket.c:633 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:643
 SYSC_sendto+0x358/0x5a0 net/socket.c:1750
 SyS_sendto+0x40/0x50 net/socket.c:1718
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4520a9
RSP: 002b:00007f9c5c458c08 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004520a9
RDX: 0000000000000001 RSI: 0000000020fd1000 RDI: 0000000000000016
RBP: 0000000000000086 R08: 0000000020e0afe4 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004bb1ee
R13: 00000000ffffffff R14: 0000000000000016 R15: 0000000000000029
Code: e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 ea 0f 00 00 48 8d 79 04 48 b8 00 00 00 00 00 fc ff df 45 8b 74 24 04 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85
RIP: ip6_setup_cork+0x274/0x15c0 net/ipv6/ip6_output.c:1168 RSP: ffff8801cc357550
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP_NV will try to get the base RTT from a socket_ops BPF program if one
is loaded. NV will then use the base RTT to bound its min RTT (its
notion of the base RTT). It uses the base RTT as an upper bound and 80%
of the base RTT as its lower bound.

In other words, NV will consider filtered RTTs larger than base RTT as a
sign of congestion. As a result, there is no minRTT inflation when there
is a lot of congestion. For example, in a DC where the RTTs are less
than 40us when there is no congestion, a base RTT value of 80us improves
the performance of NV. The difference between the uncongested RTT and
the base RTT provided represents how much queueing we are willing to
have (in practice it can be higher).

NV has been tunned to reduce congestion when there are many flows at the
cost of one flow not achieving full bandwith utilization. When a
reasonable base RTT is provided, one NV flow can now fully utilize the
full bandwidth. In addition, the performance is also improved when there
are many flows.

In the following examples the NV results are using a kernel with this
patch set (i.e. both NV results are using the new nv_loss_dec_factor).

With one host sending to another host and only one flow the
goodputs are:
  Cubic: 9.3 Gbps, NV: 5.5 Gbps, NV (baseRTT=80us): 9.2 Gbps

With 2 hosts sending to one host (1 flow per host, the goodput per flow
is:
  Cubic: 4.6 Gbps, NV: 4.5 Gbps, NV (baseRTT=80us)L 4.6 Gbps

But the RTTs seen by a ping process in the sender is:
  Cubic: 3.3ms  NV: 97us,  NV (baseRTT=80us): 146us

With a lot of flows things look even better for NV with baseRTT. Here we
have 3 hosts sending to one host. Each sending host has 6 flows: 1
stream, 4x1MB RPC, 1x10KB RPC. Cubic, NV and NV with baseRTT all fully
utilize the full available bandwidth. However, the distribution of
bandwidth among the flows is very different. For the 10KB RPC flow:
  Cubic: 27Mbps, NV: 111Mbps, NV (baseRTT=80us): 222Mbps

The 99% latencies for the 10KB flows are:
  Cubic: 26ms,  NV: 1ms,  NV (baseRTT=80us): 500us

The RTT seen by a ping process at the senders:
  Cubic: 3.2ms  NV: 720us,  NV (baseRTT=80us): 330us
Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Adding support for helper function bpf_getsockops to socket_ops BPF
programs. This patch only supports TCP_CONGESTION.
Signed-off-by: NVlad Vysotsky <vlad@cs.ucla.edu>
Acked-by: NLawrence Brakmo <brakmo@fb.com>
Acked-by: NAlexei Starovoitov <ast@fb.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Don't release call mutex at the end of rxrpc_kernel_begin_call() if the
call pointer actually holds an error value.

Fixes: 540b1c48 ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg")
Reported-by: NMarc Dionne <marc.dionne@auristor.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function tipc_sk_timeout() is more complex than necessary, and
even seems to contain an undetected bug. At one of the occurences
where we renew the timer we just order it with (HZ / 20), instead
of (jiffies + HZ / 20);

In this commit we clean up the function.
Acked-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 9cab88726929605 ("net: ethtool: Add back transceiver type")
restores the transceiver type to struct ethtool_link_settings and
convert_link_ksettings_to_legacy_settings() but forgets to remove the
error check for the same in convert_legacy_settings_to_link_ksettings().
This prevents older versions of ethtool to change link settings.

    # ethtool --version
    ethtool version 3.16

    # ethtool -s eth0 autoneg on speed 100 duplex full
    Cannot set new settings: Invalid argument
      not setting speed
      not setting duplex
      not setting autoneg

While newer versions of ethtool works.

    # ethtool --version
    ethtool version 4.10

    # ethtool -s eth0 autoneg on speed 100 duplex full
    [   57.703268] sh-eth ee700000.ethernet eth0: Link is Down
    [   59.618227] sh-eth ee700000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx

Fixes: 19cab887 ("net: ethtool: Add back transceiver type")
Signed-off-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reported-by: NRenjith R V <renjith.rv@quest-global.com>
Tested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Syzkaller stumbled upon a way to trigger
WARNING: CPU: 1 PID: 13881 at net/core/sock_reuseport.c:41
reuseport_alloc+0x306/0x3b0 net/core/sock_reuseport.c:39

There are two initialization paths for the sock_reuseport structure in a
socket: Through the udp/tcp bind paths of SO_REUSEPORT sockets or through
SO_ATTACH_REUSEPORT_[CE]BPF before bind.  The existing implementation
assumedthat the socket lock protected both of these paths when it actually
only protects the SO_ATTACH_REUSEPORT path.  Syzkaller triggered this
double allocation by running these paths concurrently.

This patch moves the check for double allocation into the reuseport_alloc
function which is protected by a global spin lock.

Fixes: e32ea7e7 ("soreuseport: fast reuseport UDP socket selection")
Fixes: c125e80b ("soreuseport: fast reuseport TCP socket selection")
Signed-off-by: NCraig Gallek <kraig@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case I placed a "fall through" comment on
its own line, which is what GCC is expecting to find.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When vlan tunnels were introduced, vlan range errors got silently
dropped and instead 0 was returned always. Restore the previous
behaviour and return errors to user-space.

Fixes: efa5356b ("bridge: per vlan dst_metadata netlink support")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Syzkaller hits WARN_ON(sk->sk_wmem_queued) in sk_stream_kill_queues
after triggering an EFAULT in __zerocopy_sg_from_iter.

On this error, skb_zerocopy_stream_iter resets the skb to its state
before the operation with __pskb_trim. It cannot kfree_skb like
datagram callers, as the skb may have data from a previous send call.

__pskb_trim calls skb_condense for unowned skbs, which adjusts their
truesize. These tcp skbuffs are owned and their truesize must add up
to sk_wmem_queued. But they match because their skb->sk is NULL until
tcp_transmit_skb.

Temporarily set skb->sk when calling __pskb_trim to signal that the
skbuffs are owned and avoid the skb_condense path.

Fixes: 52267790 ("sock: add MSG_ZEROCOPY")
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In commit ae236fb2 ("tipc: receive group membership events via
member socket") we broke the tipc_poll() function by checking the
state of the receive queue before the call to poll_sock_wait(), while
relying that state afterwards, when it might have changed.

We restore this in this commit.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All drivers are converted to use block callbacks for TC_SETUP_CLS*.
So it is now safe to remove the calls to ndo_setup_tc from cls_*
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Benefit from the newly introduced block callback infrastructure and
convert ndo_setup_tc calls for matchall offloads to block callbacks.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use the newly introduced callbacks infrastructure and call block
callbacks alongside with the existing per-netdev ndo_setup_tc.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use the newly introduced callbacks infrastructure and call block
callbacks alongside with the existing per-netdev ndo_setup_tc.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use the newly introduced callbacks infrastructure and call block
callbacks alongside with the existing per-netdev ndo_setup_tc.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Extend the tc_setup_cb_call entrypoint function originally used only for
action egress devices callbacks to call per-block callbacks as well.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce infrastructure that allows drivers to register callbacks that
are called whenever tc would offload inserted rule for a specific block.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use previously introduced extended variants of block get and put
functions. This allows to specify a binder types specific to clsact
ingress/egress which is useful for drivers to distinguish who actually
got the block.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce new type of ndo_setup_tc message to propage binding/unbinding
of a block to driver. Call this ndo whenever qdisc gets/puts a block.
Alongside with this, there's need to propagate binder type from qdisc
code down to the notifier. So introduce extended variants of
block_get/put in order to pass this info.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the UDP code there are two leftover error messages with very few meaning.
Replace them with a more descriptive error message as some users
reported them as "strange network error".
Signed-off-by: NMatteo Croce <mcroce@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The perf traces for ipv6 routing code show a relevant cost around
trace_fib6_table_lookup(), even if no trace is enabled. This is
due to the fib6_table de-referencing currently performed by the
caller.

Let's the tracing code pay this overhead, passing to the trace
helper the table pointer. This gives small but measurable
performance improvement under UDP flood.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Without the patch, when hvs_open_connection() hasn't completely established
a connection (e.g. it has changed sk->sk_state to SS_CONNECTED, but hasn't
inserted the sock into the connected queue), vsock_stream_connect() may see
the sk_state change and return the connection to the userspace, and next
when the userspace closes the connection quickly, hvs_release() may not see
the connection in the connected queue; finally hvs_open_connection()
inserts the connection into the queue, but we won't be able to purge the
connection for ever.
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Cathy Avery <cavery@redhat.com>
Cc: Rolf Neugebauer <rolf.neugebauer@docker.com>
Cc: Marcelo Cerri <marcelo.cerri@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The length of GVI (GetVersionInfo) response packet should be 40 instead
of 36. This issue was found from /sys/kernel/debug/ncsi/eth0/stats.

 # ethtool --ncsi eth0 swstats
     :
 RESPONSE     OK       TIMEOUT  ERROR
 =======================================
 GVI          0        0        2

With this applied, no error reported on GVI response packets:

 # ethtool --ncsi eth0 swstats
     :
 RESPONSE     OK       TIMEOUT  ERROR
 =======================================
 GVI          2        0        0
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NSamuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The NCSI channel has been configured to provide service if its link
monitor timer is enabled, regardless of its state (inactive or active).
So the timeout event on the link monitor indicates the out-of-service
on that channel, for which a failover is needed.

This sets NCSI_DEV_RESHUFFLE flag to enforce failover on link monitor
timeout, regardless the channel's original state (inactive or active).
Also, the link is put into "down" state to give the failing channel
lowest priority when selecting for the active channel. The state of
failing channel should be set to active in order for deinitialization
and failover to be done.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NSamuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When there are no NCSI channels probed, HWA (Hardware Arbitration)
mode is enabled. It's not correct because HWA depends on the fact:
NCSI channels exist and all of them support HWA mode. This disables
HWA when no channels are probed.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NSamuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ncsi_channel_monitor() misses stopping the channel monitor in several
places that it should, causing a WARN_ON_ONCE() to trigger when the
monitor is re-started later, eg:

[  459.040000] WARNING: CPU: 0 PID: 1093 at net/ncsi/ncsi-manage.c:269 ncsi_start_channel_monitor+0x7c/0x90
[  459.040000] CPU: 0 PID: 1093 Comm: kworker/0:3 Not tainted 4.10.17-gaca2fdd #140
[  459.040000] Hardware name: ASpeed SoC
[  459.040000] Workqueue: events ncsi_dev_work
[  459.040000] [<80010094>] (unwind_backtrace) from [<8000d950>] (show_stack+0x20/0x24)
[  459.040000] [<8000d950>] (show_stack) from [<801dbf70>] (dump_stack+0x20/0x28)
[  459.040000] [<801dbf70>] (dump_stack) from [<80018d7c>] (__warn+0xe0/0x108)
[  459.040000] [<80018d7c>] (__warn) from [<80018e70>] (warn_slowpath_null+0x30/0x38)
[  459.040000] [<80018e70>] (warn_slowpath_null) from [<803f6a08>] (ncsi_start_channel_monitor+0x7c/0x90)
[  459.040000] [<803f6a08>] (ncsi_start_channel_monitor) from [<803f7664>] (ncsi_configure_channel+0xdc/0x5fc)
[  459.040000] [<803f7664>] (ncsi_configure_channel) from [<803f8160>] (ncsi_dev_work+0xac/0x474)
[  459.040000] [<803f8160>] (ncsi_dev_work) from [<8002d244>] (process_one_work+0x1e0/0x450)
[  459.040000] [<8002d244>] (process_one_work) from [<8002d510>] (worker_thread+0x5c/0x570)
[  459.040000] [<8002d510>] (worker_thread) from [<80033614>] (kthread+0x124/0x164)
[  459.040000] [<80033614>] (kthread) from [<8000a5e8>] (ret_from_fork+0x14/0x2c)

This also updates the monitor instead of just returning if
ncsi_xmit_cmd() fails to send the get-link-status command so that the
monitor properly times out.

Fixes: e6f44ed6 "net/ncsi: Package and channel management"
Signed-off-by: NSamuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Correct the value of the HNCDSC AEN packet.
Fixes: 7a82ecf4 "net/ncsi: NCSI AEN packet handler"
Signed-off-by: NSamuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ipv4_default_advmss() incorrectly uses the device MTU instead
of the route provided one. IPv6 has the proper behavior,
lets harmonize the two protocols.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzkaller got crashes in packet_getsockopt() processing
PACKET_ROLLOVER_STATS command while another thread was managing
to change po->rollover

Using RCU will fix this bug. We might later add proper RCU annotations
for sparse sake.

In v2: I replaced kfree(rollover) in fanout_add() to kfree_rcu()
variant, as spotted by John.

Fixes: a9b63918 ("packet: rollover statistics")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: John Sperbeck <jsperbeck@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syn_data was allocated by sk_stream_alloc_skb(), meaning
its destructor and _skb_refdst fields are mangled.

We need to call tcp_skb_tsorted_anchor_cleanup() before
calling kfree_skb() or kernel crashes.

Bug was reported by syzkaller bot.

Fixes: e2080072 ("tcp: new list for sent but unacked skbs for RACK recovery")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit 2b760fcf ("ipv6: hook up exception table to store
dst cache") partially reverted the commit 1e2ea8ad ("ipv6: set
dst.obsolete when a cached route has expired").

As a result, RTF_CACHE dst referenced outside the fib tree will
not be removed until the next sernum change; dst_check() does not
fail on aged-out dst, and dst->__refcnt can't decrease: the aged
out dst will stay valid for a potentially unlimited time after the
timeout expiration.

This change explicitly removes RTF_CACHE dst from the fib tree when
aged out. The rt6_remove_exception() logic will then obsolete the
dst and other entities will drop the related reference on next
dst_check().

pMTU exceptions are not aged-out, and are removed from the exception
table only when the - usually considerably longer - ip6_rt_mtu_expires
timeout expires.

v1 -> v2:
  - do not touch dst.obsolete in rt6_remove_exception(), not needed
v2 -> v3:
  - take care of pMTU exceptions, too

Fixes: 2b760fcf ("ipv6: hook up exception table to store dst cache")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NWei Wang <weiwan@google.com>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>