There are two network devices(veth1 and veth3) in ns1, and ipvlan1 with
L3S mode and ipvlan2 with L2 mode are created based on them as
figure (1). In this case, ipvlan_register_nf_hook() will be called to
register nf hook which is needed by ipvlans in L3S mode in ns1 and value
of ipvl_nf_hook_refcnt is set to 1.

(1)
           ns1                           ns2
      ------------                  ------------

   veth1--ipvlan1 (L3S)

   veth3--ipvlan2 (L2)

(2)
           ns1                           ns2
      ------------                  ------------

   veth1--ipvlan1 (L3S)

         ipvlan2 (L2)                  veth3
     |                                  |
     |------->-------->--------->--------
                    migrate

When veth3 migrates from ns1 to ns2 as figure (2), veth3 will register in
ns2 and calls call_netdevice_notifiers with NETDEV_REGISTER event:

dev_change_net_namespace
    call_netdevice_notifiers
        ipvlan_device_event
            ipvlan_migrate_l3s_hook
                ipvlan_register_nf_hook(newnet)      (I)
                ipvlan_unregister_nf_hook(oldnet)    (II)

In function ipvlan_migrate_l3s_hook(), ipvl_nf_hook_refcnt in ns1 is not 0
since veth1 with ipvlan1 still in ns1, (I) and (II) will be called to
register nf_hook in ns2 and unregister nf_hook in ns1. As a result,
ipvl_nf_hook_refcnt in ns1 is decreased incorrectly and this in ns2
is increased incorrectly. When the second net namespace is removed, a
reference count leak warning in ipvlan_ns_exit() will be triggered.

This patch add a check before ipvlan_migrate_l3s_hook() is called. The
warning can be triggered as follows:

$ ip netns add ns1
$ ip netns add ns2
$ ip netns exec ns1 ip link add veth1 type veth peer name veth2
$ ip netns exec ns1 ip link add veth3 type veth peer name veth4
$ ip netns exec ns1 ip link add ipv1 link veth1 type ipvlan mode l3s
$ ip netns exec ns1 ip link add ipv2 link veth3 type ipvlan mode l2
$ ip netns exec ns1 ip link set veth3 netns ns2
$ ip net del ns2

Fixes: 3133822f5ac1 ("ipvlan: use pernet operations and restrict l3s hooks to master netns")
Signed-off-by: Lu Wei <luwei32@huawei.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230817145449.141827-1-luwei32@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/lib/bpf/ringbuf.c
  927cbb478adf ("libbpf: Handle size overflow for ringbuf mmap")
  b486d19a0ab0 ("libbpf: checkpatch: Fixed code alignments in ringbuf.c")
https://lore.kernel.org/all/20221121122707.44d1446a@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Recently syzkaller discovered the issue of disappearing lower
device (NETDEV_UNREGISTER) while the virtual device (like
macvlan) is still having it as a lower device. So it's just
a matter of time similar discovery will be made for IPvlan
device setup. So fixing it preemptively. Also while at it,
add a refcount tracker.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Now that the 32bit UP oddity is gone and 32bit uses always a sequence
count, there is no need for the fetch_irq() variants anymore.

Convert to the regular interface.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> # for CAN
Link: https://lore.kernel.org/r/20220830201457.7984-1-wsa+renesas@sang-engineering.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

As explained in commit 316580b69d0a ("u64_stats: provide u64_stats_t type")
we should use u64_stats_t and related accessors to avoid load/store tearing.

Add READ_ONCE() when reading rx_errs & tx_drps.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

To make later patches smaller create a helper for inheriting
the TSO limitations of a lower device. The TSO in the name
is not an accident, subsequent patches will replace GSO
with TSO in more names.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

The 'if (dev)' statement already move into dev_{put , hold}, so remove
redundant if statements.

Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

dev->gso_max_segs is written under RTNL protection, or when the device is
not yet visible, but is read locklessly.

Add netif_set_gso_max_segs() helper.

Add the READ_ONCE()/WRITE_ONCE() pairs, and use netif_set_gso_max_segs()
where we can to better document what is going on.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dev->gso_max_size is written under RTNL protection, or when the device is
not yet visible, but is read locklessly.

Add the READ_ONCE()/WRITE_ONCE() pairs, and use netif_set_gso_max_size()
where we can to better document what is going on.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>