1. 13 May, 2020 3 commits
  2. 12 May, 2020 7 commits
  3. 11 May, 2020 4 commits
    • David S. Miller's avatar
      Merge branch 'net-ipa-fix-cleanup-after-modem-crash' · 1abfb181
      David S. Miller authored
      Alex Elder says:
      
      ====================
      net: ipa: fix cleanup after modem crash
      
      The first patch in this series fixes a bug where the size of a data
      transfer request was never set, meaning it was 0.  The consequence
      of this was that such a transfer request would never complete if
      attempted, and led to a hung task timeout.
      
      This data transfer is required for cleaning up IPA hardware state
      when recovering from a modem crash.  The code to implement this
      cleanup is already present, but its use was commented out because
      it hit the bug described above.  So the second patch in this series
      enables the use of that "tag process" cleanup code.
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1abfb181
    • Alex Elder's avatar
      net: ipa: use tag process on modem crash · 2c4bb809
      Alex Elder authored
      One part of recovering from a modem crash is performing a "tag
      sequence" of several IPA immediate commands, to clear the hardware
      pipeline.  The sequence ends with a data transfer request on the
      command endpoint (which is not otherwise done).  Unfortunately,
      attempting to do the data transfer led to a hang, so that request
      plus two other commands were commented out.
      
      The previous commit fixes the bug that was causing that hang.  And
      with that bug fixed we can properly issue the tag sequence when the
      modem crashes, to return the hardware to a known state.
      Signed-off-by: default avatarAlex Elder <elder@linaro.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2c4bb809
    • Alex Elder's avatar
      net: ipa: set DMA length in gsi_trans_cmd_add() · c781e1d4
      Alex Elder authored
      When a command gets added to a transaction for the AP->command
      channel we set the DMA address of its scatterlist entry, but not
      its DMA length.  Fix this bug.
      Signed-off-by: default avatarAlex Elder <elder@linaro.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c781e1d4
    • Luo bin's avatar
      hinic: fix a bug of ndo_stop · e8a1b0ef
      Luo bin authored
      if some function in ndo_stop interface returns failure because of
      hardware fault, must go on excuting rest steps rather than return
      failure directly, otherwise will cause memory leak.And bump the
      timeout for SET_FUNC_STATE to ensure that cmd won't return failure
      when hw is busy. Otherwise hw may stomp host memory if we free
      memory regardless of the return value of SET_FUNC_STATE.
      
      Fixes: 51ba902a ("net-next/hinic: Initialize hw interface")
      Signed-off-by: default avatarLuo bin <luobin9@huawei.com>
      Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      e8a1b0ef
  4. 10 May, 2020 2 commits
    • Florian Fainelli's avatar
      net: dsa: loop: Add module soft dependency · 3047211c
      Florian Fainelli authored
      There is a soft dependency against dsa_loop_bdinfo.ko which sets up the
      MDIO device registration, since there are no symbols referenced by
      dsa_loop.ko, there is no automatic loading of dsa_loop_bdinfo.ko which
      is needed.
      
      Fixes: 98cd1552 ("net: dsa: Mock-up driver")
      Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
      Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      3047211c
    • Zefan Li's avatar
      netprio_cgroup: Fix unlimited memory leak of v2 cgroups · 090e28b2
      Zefan Li authored
      If systemd is configured to use hybrid mode which enables the use of
      both cgroup v1 and v2, systemd will create new cgroup on both the default
      root (v2) and netprio_cgroup hierarchy (v1) for a new session and attach
      task to the two cgroups. If the task does some network thing then the v2
      cgroup can never be freed after the session exited.
      
      One of our machines ran into OOM due to this memory leak.
      
      In the scenario described above when sk_alloc() is called
      cgroup_sk_alloc() thought it's in v2 mode, so it stores
      the cgroup pointer in sk->sk_cgrp_data and increments
      the cgroup refcnt, but then sock_update_netprioidx()
      thought it's in v1 mode, so it stores netprioidx value
      in sk->sk_cgrp_data, so the cgroup refcnt will never be freed.
      
      Currently we do the mode switch when someone writes to the ifpriomap
      cgroup control file. The easiest fix is to also do the switch when
      a task is attached to a new cgroup.
      
      Fixes: bd1060a1 ("sock, cgroup: add sock->sk_cgroup")
      Reported-by: default avatarYang Yingliang <yangyingliang@huawei.com>
      Tested-by: default avatarYang Yingliang <yangyingliang@huawei.com>
      Signed-off-by: default avatarZefan Li <lizefan@huawei.com>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      090e28b2
  5. 09 May, 2020 8 commits
  6. 08 May, 2020 6 commits
    • Kelly Littlepage's avatar
      net: tcp: fix rx timestamp behavior for tcp_recvmsg · cc4de047
      Kelly Littlepage authored
      The stated intent of the original commit is to is to "return the timestamp
      corresponding to the highest sequence number data returned." The current
      implementation returns the timestamp for the last byte of the last fully
      read skb, which is not necessarily the last byte in the recv buffer. This
      patch converts behavior to the original definition, and to the behavior of
      the previous draft versions of commit 98aaa913 ("tcp: Extend
      SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg") which also match this
      behavior.
      
      Fixes: 98aaa913 ("tcp: Extend SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg")
      Co-developed-by: default avatarIris Liu <iris@onechronos.com>
      Signed-off-by: default avatarIris Liu <iris@onechronos.com>
      Signed-off-by: default avatarKelly Littlepage <kelly@onechronos.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
      Acked-by: default avatarWillem de Bruijn <willemb@google.com>
      Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      cc4de047
    • Cong Wang's avatar
      net: fix a potential recursive NETDEV_FEAT_CHANGE · dd912306
      Cong Wang authored
      syzbot managed to trigger a recursive NETDEV_FEAT_CHANGE event
      between bonding master and slave. I managed to find a reproducer
      for this:
      
        ip li set bond0 up
        ifenslave bond0 eth0
        brctl addbr br0
        ethtool -K eth0 lro off
        brctl addif br0 bond0
        ip li set br0 up
      
      When a NETDEV_FEAT_CHANGE event is triggered on a bonding slave,
      it captures this and calls bond_compute_features() to fixup its
      master's and other slaves' features. However, when syncing with
      its lower devices by netdev_sync_lower_features() this event is
      triggered again on slaves when the LRO feature fails to change,
      so it goes back and forth recursively until the kernel stack is
      exhausted.
      
      Commit 17b85d29 intentionally lets __netdev_update_features()
      return -1 for such a failure case, so we have to just rely on
      the existing check inside netdev_sync_lower_features() and skip
      NETDEV_FEAT_CHANGE event only for this specific failure case.
      
      Fixes: fd867d51 ("net/core: generic support for disabling netdev features down stack")
      Reported-by: syzbot+e73ceacfd8560cc8a3ca@syzkaller.appspotmail.com
      Reported-by: syzbot+c2fb6f9ddcea95ba49b5@syzkaller.appspotmail.com
      Cc: Jarod Wilson <jarod@redhat.com>
      Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Reviewed-by: default avatarJay Vosburgh <jay.vosburgh@canonical.com>
      Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
      Acked-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      dd912306
    • Paolo Abeni's avatar
      mptcp: set correct vfs info for subflows · 7d14b0d2
      Paolo Abeni authored
      When a subflow is created via mptcp_subflow_create_socket(),
      a new 'struct socket' is allocated, with a new i_ino value.
      
      When inspecting TCP sockets via the procfs and or the diag
      interface, the above ones are not related to the process owning
      the MPTCP master socket, even if they are a logical part of it
      ('ss -p' shows an empty process field)
      
      Additionally, subflows created by the path manager get
      the uid/gid from the running workqueue.
      
      Subflows are part of the owning MPTCP master socket, let's
      adjust the vfs info to reflect this.
      
      After this patch, 'ss' correctly displays subflows as belonging
      to the msk socket creator.
      
      Fixes: 2303f994 ("mptcp: Associate MPTCP context with TCP socket")
      Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      7d14b0d2
    • Chuhong Yuan's avatar
      net: microchip: encx24j600: add missed kthread_stop · ff8ce319
      Chuhong Yuan authored
      This driver calls kthread_run() in probe, but forgets to call
      kthread_stop() in probe failure and remove.
      Add the missed kthread_stop() to fix it.
      Signed-off-by: default avatarChuhong Yuan <hslester96@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ff8ce319
    • Maciej Żenczykowski's avatar
      Revert "ipv6: add mtu lock check in __ip6_rt_update_pmtu" · 09454fd0
      Maciej Żenczykowski authored
      This reverts commit 19bda36c:
      
      | ipv6: add mtu lock check in __ip6_rt_update_pmtu
      |
      | Prior to this patch, ipv6 didn't do mtu lock check in ip6_update_pmtu.
      | It leaded to that mtu lock doesn't really work when receiving the pkt
      | of ICMPV6_PKT_TOOBIG.
      |
      | This patch is to add mtu lock check in __ip6_rt_update_pmtu just as ipv4
      | did in __ip_rt_update_pmtu.
      
      The above reasoning is incorrect.  IPv6 *requires* icmp based pmtu to work.
      There's already a comment to this effect elsewhere in the kernel:
      
        $ git grep -p -B1 -A3 'RTAX_MTU lock'
        net/ipv6/route.c=4813=
      
        static int rt6_mtu_change_route(struct fib6_info *f6i, void *p_arg)
        ...
          /* In IPv6 pmtu discovery is not optional,
             so that RTAX_MTU lock cannot disable it.
             We still use this lock to block changes
             caused by addrconf/ndisc.
          */
      
      This reverts to the pre-4.9 behaviour.
      
      Cc: Eric Dumazet <edumazet@google.com>
      Cc: Willem de Bruijn <willemb@google.com>
      Cc: Xin Long <lucien.xin@gmail.com>
      Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
      Signed-off-by: default avatarMaciej Żenczykowski <maze@google.com>
      Fixes: 19bda36c ("ipv6: add mtu lock check in __ip6_rt_update_pmtu")
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      09454fd0
    • Arnd Bergmann's avatar
      net: bareudp: avoid uninitialized variable warning · ee287556
      Arnd Bergmann authored
      clang points out that building without IPv6 would lead to returning
      an uninitialized variable if a packet with family!=AF_INET is
      passed into bareudp_udp_encap_recv():
      
      drivers/net/bareudp.c:139:6: error: variable 'err' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
              if (family == AF_INET)
                  ^~~~~~~~~~~~~~~~~
      drivers/net/bareudp.c:146:15: note: uninitialized use occurs here
              if (unlikely(err)) {
                           ^~~
      include/linux/compiler.h:78:42: note: expanded from macro 'unlikely'
       # define unlikely(x)    __builtin_expect(!!(x), 0)
                                                  ^
      drivers/net/bareudp.c:139:2: note: remove the 'if' if its condition is always true
              if (family == AF_INET)
              ^~~~~~~~~~~~~~~~~~~~~~
      
      This cannot happen in practice, so change the condition in a way that
      gcc sees the IPv4 case as unconditionally true here.
      For consistency, change all the similar constructs in this file the
      same way, using "if(IS_ENABLED())" instead of #if IS_ENABLED()".
      
      Fixes: 571912c6 ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.")
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Reviewed-by: default avatarNathan Chancellor <natechancellor@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ee287556
  7. 07 May, 2020 10 commits
    • Geert Uytterhoeven's avatar
      net: hisilicon: Make CONFIG_HNS invisible · 8aef1994
      Geert Uytterhoeven authored
      The HNS config symbol enables the framework support for the Hisilicon
      Network Subsystem.  It is already selected by all of its users, so there
      is no reason to make it visible.
      Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      8aef1994
    • Oliver Neukum's avatar
      usb: hso: correct debug message · 1a10186e
      Oliver Neukum authored
      If you do not find the OUT endpoint, you should say so,
      rather than copy the error message for the IN endpoint.
      Presumably a copy and paste error.
      Signed-off-by: default avatarOliver Neukum <oneukum@suse.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1a10186e
    • Maciej Żenczykowski's avatar
      net: remove spurious declaration of tcp_default_init_rwnd() · 64082b67
      Maciej Żenczykowski authored
      it doesn't actually exist...
      
      Test: builds and 'git grep tcp_default_init_rwnd' comes up empty
      Signed-off-by: default avatarMaciej Żenczykowski <maze@google.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      64082b67
    • Michael S. Tsirkin's avatar
      virtio_net: fix lockdep warning on 32 bit · 01c32598
      Michael S. Tsirkin authored
      When we fill up a receive VQ, try_fill_recv currently tries to count
      kicks using a 64 bit stats counter. Turns out, on a 32 bit kernel that
      uses a seqcount. sequence counts are "lock" constructs where you need to
      make sure that writers are serialized.
      
      In turn, this means that we mustn't run two try_fill_recv concurrently.
      Which of course we don't. We do run try_fill_recv sometimes from a
      softirq napi context, and sometimes from a fully preemptible context,
      but the later always runs with napi disabled.
      
      However, when it comes to the seqcount, lockdep is trying to enforce the
      rule that the same lock isn't accessed from preemptible and softirq
      context - it doesn't know about napi being enabled/disabled. This causes
      a false-positive warning:
      
      WARNING: inconsistent lock state
      ...
      inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
      
      As a work around, shut down the warning by switching
      to u64_stats_update_begin_irqsave - that works by disabling
      interrupts on 32 bit only, is a NOP on 64 bit.
      Reported-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Suggested-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      01c32598
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net · a811c1fa
      Linus Torvalds authored
      Pull networking fixes from David Miller:
      
       1) Fix reference count leaks in various parts of batman-adv, from Xiyu
          Yang.
      
       2) Update NAT checksum even when it is zero, from Guillaume Nault.
      
       3) sk_psock reference count leak in tls code, also from Xiyu Yang.
      
       4) Sanity check TCA_FQ_CODEL_DROP_BATCH_SIZE netlink attribute in
          fq_codel, from Eric Dumazet.
      
       5) Fix panic in choke_reset(), also from Eric Dumazet.
      
       6) Fix VLAN accel handling in bnxt_fix_features(), from Michael Chan.
      
       7) Disallow out of range quantum values in sch_sfq, from Eric Dumazet.
      
       8) Fix crash in x25_disconnect(), from Yue Haibing.
      
       9) Don't pass pointer to local variable back to the caller in
          nf_osf_hdr_ctx_init(), from Arnd Bergmann.
      
      10) Wireguard should use the ECN decap helper functions, from Toke
          Høiland-Jørgensen.
      
      11) Fix command entry leak in mlx5 driver, from Moshe Shemesh.
      
      12) Fix uninitialized variable access in mptcp's
          subflow_syn_recv_sock(), from Paolo Abeni.
      
      13) Fix unnecessary out-of-order ingress frame ordering in macsec, from
          Scott Dial.
      
      14) IPv6 needs to use a global serial number for dst validation just
          like ipv4, from David Ahern.
      
      15) Fix up PTP_1588_CLOCK deps, from Clay McClure.
      
      16) Missing NLM_F_MULTI flag in gtp driver netlink messages, from
          Yoshiyuki Kurauchi.
      
      17) Fix a regression in that dsa user port errors should not be fatal,
          from Florian Fainelli.
      
      18) Fix iomap leak in enetc driver, from Dejin Zheng.
      
      19) Fix use after free in lec_arp_clear_vccs(), from Cong Wang.
      
      20) Initialize protocol value earlier in neigh code paths when
          generating events, from Roman Mashak.
      
      21) netdev_update_features() must be called with RTNL mutex in macsec
          driver, from Antoine Tenart.
      
      22) Validate untrusted GSO packets even more strictly, from Willem de
          Bruijn.
      
      23) Wireguard decrypt worker needs a cond_resched(), from Jason
          Donenfeld.
      
      * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (111 commits)
        net: flow_offload: skip hw stats check for FLOW_ACTION_HW_STATS_DONT_CARE
        MAINTAINERS: put DYNAMIC INTERRUPT MODERATION in proper order
        wireguard: send/receive: use explicit unlikely branch instead of implicit coalescing
        wireguard: selftests: initalize ipv6 members to NULL to squelch clang warning
        wireguard: send/receive: cond_resched() when processing worker ringbuffers
        wireguard: socket: remove errant restriction on looping to self
        wireguard: selftests: use normal kernel stack size on ppc64
        net: ethernet: ti: am65-cpsw-nuss: fix irqs type
        ionic: Use debugfs_create_bool() to export bool
        net: dsa: Do not leave DSA master with NULL netdev_ops
        net: dsa: remove duplicate assignment in dsa_slave_add_cls_matchall_mirred
        net: stricter validation of untrusted gso packets
        seg6: fix SRH processing to comply with RFC8754
        net: mscc: ocelot: ANA_AUTOAGE_AGE_PERIOD holds a value in seconds, not ms
        net: dsa: ocelot: the MAC table on Felix is twice as large
        net: dsa: sja1105: the PTP_CLK extts input reacts on both edges
        selftests: net: tcp_mmap: fix SO_RCVLOWAT setting
        net: hsr: fix incorrect type usage for protocol variable
        net: macsec: fix rtnl locking issue
        net: mvpp2: cls: Prevent buffer overflow in mvpp2_ethtool_cls_rule_del()
        ...
      a811c1fa
    • Pablo Neira Ayuso's avatar
      net: flow_offload: skip hw stats check for FLOW_ACTION_HW_STATS_DONT_CARE · 16f80360
      Pablo Neira Ayuso authored
      This patch adds FLOW_ACTION_HW_STATS_DONT_CARE which tells the driver
      that the frontend does not need counters, this hw stats type request
      never fails. The FLOW_ACTION_HW_STATS_DISABLED type explicitly requests
      the driver to disable the stats, however, if the driver cannot disable
      counters, it bails out.
      
      TCA_ACT_HW_STATS_* maintains the 1:1 mapping with FLOW_ACTION_HW_STATS_*
      except by disabled which is mapped to FLOW_ACTION_HW_STATS_DISABLED
      (this is 0 in tc). Add tc_act_hw_stats() to perform the mapping between
      TCA_ACT_HW_STATS_* and FLOW_ACTION_HW_STATS_*.
      
      Fixes: 319a1d19 ("flow_offload: check for basic action hw stats type")
      Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      16f80360
    • Lukas Bulwahn's avatar
      MAINTAINERS: put DYNAMIC INTERRUPT MODERATION in proper order · b0956956
      Lukas Bulwahn authored
      Commit 9b038086 ("docs: networking: convert DIM to RST") added a new
      file entry to DYNAMIC INTERRUPT MODERATION to the end, and not following
      alphabetical order.
      
      So, ./scripts/checkpatch.pl -f MAINTAINERS complains:
      
        WARNING: Misordered MAINTAINERS entry - list file patterns in alphabetic
        order
        #5966: FILE: MAINTAINERS:5966:
        +F:      lib/dim/
        +F:      Documentation/networking/net_dim.rst
      
      Reorder the file entries to keep MAINTAINERS nicely ordered.
      Signed-off-by: default avatarLukas Bulwahn <lukas.bulwahn@gmail.com>
      Acked-by: default avatarJakub Kicinski <kuba@kernel.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b0956956
    • David S. Miller's avatar
      Merge branch 'wireguard-fixes' · d3f3e6ac
      David S. Miller authored
      Jason A. Donenfeld says:
      
      ====================
      wireguard fixes for 5.7-rc5
      
      With Ubuntu and Debian having backported this into their kernels, we're
      finally seeing testing from places we hadn't seen prior, which is nice.
      With that comes more fixes:
      
      1) The CI for PPC64 was running with extremely small stacks for 64-bit,
         causing spurious crashes in surprising places.
      
      2) There's was an old leftover routing loop restriction, which no longer
         makes sense given the queueing architecture, and was causing problems
         for people who really did want nested routing.
      
      3) Not yielding our kthread on CONFIG_PREEMPT_VOLUNTARY systems caused
         RCU stalls and other issues, reported by Wang Jian, with the fix
         suggested by Sultan Alsawaf.
      
      4) Clang spewed warnings in a selftest for CONFIG_IPV6=n, reported by
         Arnd Bergmann.
      
      5) A complicated if statement was simplified to an assignment while also
         making the likely/unlikely hinting more correct and simple, and
         increasing readability, suggested by Sultan.
      
      Patches (2) and (3) have Fixes: lines and are probably good candidates
      for stable.
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d3f3e6ac
    • Jason A. Donenfeld's avatar
      wireguard: send/receive: use explicit unlikely branch instead of implicit coalescing · 243f2148
      Jason A. Donenfeld authored
      It's very unlikely that send will become true. It's nearly always false
      between 0 and 120 seconds of a session, and in most cases becomes true
      only between 120 and 121 seconds before becoming false again. So,
      unlikely(send) is clearly the right option here.
      
      What happened before was that we had this complex boolean expression
      with multiple likely and unlikely clauses nested. Since this is
      evaluated left-to-right anyway, the whole thing got converted to
      unlikely. So, we can clean this up to better represent what's going on.
      
      The generated code is the same.
      Suggested-by: default avatarSultan Alsawaf <sultan@kerneltoast.com>
      Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      243f2148
    • Jason A. Donenfeld's avatar
      wireguard: selftests: initalize ipv6 members to NULL to squelch clang warning · 4fed818e
      Jason A. Donenfeld authored
      Without setting these to NULL, clang complains in certain
      configurations that have CONFIG_IPV6=n:
      
      In file included from drivers/net/wireguard/ratelimiter.c:223:
      drivers/net/wireguard/selftest/ratelimiter.c:173:34: error: variable 'skb6' is uninitialized when used here [-Werror,-Wuninitialized]
                      ret = timings_test(skb4, hdr4, skb6, hdr6, &test_count);
                                                     ^~~~
      drivers/net/wireguard/selftest/ratelimiter.c:123:29: note: initialize the variable 'skb6' to silence this warning
              struct sk_buff *skb4, *skb6;
                                         ^
                                          = NULL
      drivers/net/wireguard/selftest/ratelimiter.c:173:40: error: variable 'hdr6' is uninitialized when used here [-Werror,-Wuninitialized]
                      ret = timings_test(skb4, hdr4, skb6, hdr6, &test_count);
                                                           ^~~~
      drivers/net/wireguard/selftest/ratelimiter.c:125:22: note: initialize the variable 'hdr6' to silence this warning
              struct ipv6hdr *hdr6;
                                  ^
      
      We silence this warning by setting the variables to NULL as the warning
      suggests.
      Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4fed818e