1. 05 Aug, 2023 5 commits
    • Andrea Claudi's avatar
      selftests: mptcp: join: fix 'delete and re-add' test · aaf2123a
      Andrea Claudi authored
      mptcp_join 'delete and re-add' test fails when using ip mptcp:
      
        $ ./mptcp_join.sh -iI
        <snip>
        002 delete and re-add                    before delete[ ok ]
                                                 mptcp_info subflows=1         [ ok ]
        Error: argument "ADDRESS" is wrong: invalid for non-zero id address
                                                 after delete[fail] got 2:2 subflows expected 1
      
      This happens because endpoint delete includes an ip address while id is
      not 0, contrary to what is indicated in the ip mptcp man page:
      
      "When used with the delete id operation, an IFADDR is only included when
      the ID is 0."
      
      This fixes the issue using the $addr variable in pm_nl_del_endpoint()
      only when id is 0.
      
      Fixes: 34aa6e3b ("selftests: mptcp: add ip mptcp wrappers")
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarAndrea Claudi <aclaudi@redhat.com>
      Reviewed-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
      Signed-off-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
      Link: https://lore.kernel.org/r/20230803-upstream-net-20230803-misc-fixes-6-5-v1-1-6671b1ab11cc@tessares.netSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      aaf2123a
    • Jakub Kicinski's avatar
      Merge branch 'tunnels-fix-ipv4-pmtu-icmp-checksum' · ec935188
      Jakub Kicinski authored
      Florian Westphal says:
      
      ====================
      tunnels: fix ipv4 pmtu icmp checksum
      
      The checksum of the generated ipv4 icmp pmtud message is
      only correct if the skb that causes the icmp error generation
      is linear.
      
      Fix this and add a selftest for this.
      ====================
      
      Link: https://lore.kernel.org/r/20230803152653.29535-1-fw@strlen.deSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      ec935188
    • Florian Westphal's avatar
      selftests: net: test vxlan pmtu exceptions with tcp · 136a1b43
      Florian Westphal authored
      TCP might get stuck if a nonlinear skb exceeds the path MTU,
      icmp error contains an incorrect icmp checksum in that case.
      
      Extend the existing test for vxlan to also send at least 1MB worth of
      data via TCP in addition to the existing 'large icmp packet adds
      route exception'.
      
      On my test VM this fails due to 0-size output file without
      "tunnels: fix kasan splat when generating ipv4 pmtu error".
      Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
      Link: https://lore.kernel.org/r/20230803152653.29535-3-fw@strlen.deSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      136a1b43
    • Florian Westphal's avatar
      tunnels: fix kasan splat when generating ipv4 pmtu error · 6a7ac3d2
      Florian Westphal authored
      If we try to emit an icmp error in response to a nonliner skb, we get
      
      BUG: KASAN: slab-out-of-bounds in ip_compute_csum+0x134/0x220
      Read of size 4 at addr ffff88811c50db00 by task iperf3/1691
      CPU: 2 PID: 1691 Comm: iperf3 Not tainted 6.5.0-rc3+ #309
      [..]
       kasan_report+0x105/0x140
       ip_compute_csum+0x134/0x220
       iptunnel_pmtud_build_icmp+0x554/0x1020
       skb_tunnel_check_pmtu+0x513/0xb80
       vxlan_xmit_one+0x139e/0x2ef0
       vxlan_xmit+0x1867/0x2760
       dev_hard_start_xmit+0x1ee/0x4f0
       br_dev_queue_push_xmit+0x4d1/0x660
       [..]
      
      ip_compute_csum() cannot deal with nonlinear skbs, so avoid it.
      After this change, splat is gone and iperf3 is no longer stuck.
      
      Fixes: 4cb47a86 ("tunnels: PMTU discovery support for directly bridged IP packets")
      Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
      Link: https://lore.kernel.org/r/20230803152653.29535-2-fw@strlen.deSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      6a7ac3d2
    • Eric Dumazet's avatar
      net/packet: annotate data-races around tp->status · 8a989617
      Eric Dumazet authored
      Another syzbot report [1] is about tp->status lockless reads
      from __packet_get_status()
      
      [1]
      BUG: KCSAN: data-race in __packet_rcv_has_room / __packet_set_status
      
      write to 0xffff888117d7c080 of 8 bytes by interrupt on cpu 0:
      __packet_set_status+0x78/0xa0 net/packet/af_packet.c:407
      tpacket_rcv+0x18bb/0x1a60 net/packet/af_packet.c:2483
      deliver_skb net/core/dev.c:2173 [inline]
      __netif_receive_skb_core+0x408/0x1e80 net/core/dev.c:5337
      __netif_receive_skb_one_core net/core/dev.c:5491 [inline]
      __netif_receive_skb+0x57/0x1b0 net/core/dev.c:5607
      process_backlog+0x21f/0x380 net/core/dev.c:5935
      __napi_poll+0x60/0x3b0 net/core/dev.c:6498
      napi_poll net/core/dev.c:6565 [inline]
      net_rx_action+0x32b/0x750 net/core/dev.c:6698
      __do_softirq+0xc1/0x265 kernel/softirq.c:571
      invoke_softirq kernel/softirq.c:445 [inline]
      __irq_exit_rcu+0x57/0xa0 kernel/softirq.c:650
      sysvec_apic_timer_interrupt+0x6d/0x80 arch/x86/kernel/apic/apic.c:1106
      asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
      smpboot_thread_fn+0x33c/0x4a0 kernel/smpboot.c:112
      kthread+0x1d7/0x210 kernel/kthread.c:379
      ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
      
      read to 0xffff888117d7c080 of 8 bytes by interrupt on cpu 1:
      __packet_get_status net/packet/af_packet.c:436 [inline]
      packet_lookup_frame net/packet/af_packet.c:524 [inline]
      __tpacket_has_room net/packet/af_packet.c:1255 [inline]
      __packet_rcv_has_room+0x3f9/0x450 net/packet/af_packet.c:1298
      tpacket_rcv+0x275/0x1a60 net/packet/af_packet.c:2285
      deliver_skb net/core/dev.c:2173 [inline]
      dev_queue_xmit_nit+0x38a/0x5e0 net/core/dev.c:2243
      xmit_one net/core/dev.c:3574 [inline]
      dev_hard_start_xmit+0xcf/0x3f0 net/core/dev.c:3594
      __dev_queue_xmit+0xefb/0x1d10 net/core/dev.c:4244
      dev_queue_xmit include/linux/netdevice.h:3088 [inline]
      can_send+0x4eb/0x5d0 net/can/af_can.c:276
      bcm_can_tx+0x314/0x410 net/can/bcm.c:302
      bcm_tx_timeout_handler+0xdb/0x260
      __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
      __hrtimer_run_queues+0x217/0x700 kernel/time/hrtimer.c:1749
      hrtimer_run_softirq+0xd6/0x120 kernel/time/hrtimer.c:1766
      __do_softirq+0xc1/0x265 kernel/softirq.c:571
      run_ksoftirqd+0x17/0x20 kernel/softirq.c:939
      smpboot_thread_fn+0x30a/0x4a0 kernel/smpboot.c:164
      kthread+0x1d7/0x210 kernel/kthread.c:379
      ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
      
      value changed: 0x0000000000000000 -> 0x0000000020000081
      
      Reported by Kernel Concurrency Sanitizer on:
      CPU: 1 PID: 19 Comm: ksoftirqd/1 Not tainted 6.4.0-syzkaller #0
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
      
      Fixes: 69e3c75f ("net: TX_RING and packet mmap")
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
      Link: https://lore.kernel.org/r/20230803145600.2937518-1-edumazet@google.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      8a989617
  2. 04 Aug, 2023 6 commits
  3. 03 Aug, 2023 23 commits
  4. 02 Aug, 2023 6 commits
    • Linus Torvalds's avatar
      Merge tag 'exfat-for-6.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat · 4b954598
      Linus Torvalds authored
      Pull exfat fixes from Namjae Jeon:
      
       - Fix page allocation failure from allocation bitmap by using
         kvmalloc_array/kvfree
      
       - Add the check to validate if filename entries exceeds max filename
         length
      
       - Fix potential deadlock condition from dir_emit*()
      
      * tag 'exfat-for-6.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
        exfat: release s_lock before calling dir_emit()
        exfat: check if filename entries exceeds max filename length
        exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree
      4b954598
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 79d65ee5
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "Three small fixes, all in drivers"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: pm80xx: Fix error return code in pm8001_pci_probe()
        scsi: zfcp: Defer fc_rport blocking until after ADISC response
        scsi: storvsc: Limit max_sectors for virtual Fibre Channel devices
      79d65ee5
    • ndesaulniers@google.com's avatar
      word-at-a-time: use the same return type for has_zero regardless of endianness · 79e8328e
      ndesaulniers@google.com authored
      Compiling big-endian targets with Clang produces the diagnostic:
      
        fs/namei.c:2173:13: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical]
      	} while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
      	          ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                                     ||
        fs/namei.c:2173:13: note: cast one or both operands to int to silence this warning
      
      It appears that when has_zero was introduced, two definitions were
      produced with different signatures (in particular different return
      types).
      
      Looking at the usage in hash_name() in fs/namei.c, I suspect that
      has_zero() is meant to be invoked twice per while loop iteration; using
      logical-or would not update `bdata` when `a` did not have zeros.  So I
      think it's preferred to always return an unsigned long rather than a
      bool than update the while loop in hash_name() to use a logical-or
      rather than bitwise-or.
      
      [ Also changed powerpc version to do the same  - Linus ]
      
      Link: https://github.com/ClangBuiltLinux/linux/issues/1832
      Link: https://lore.kernel.org/lkml/20230801-bitwise-v1-1-799bec468dc4@google.com/
      Fixes: 36126f8f ("word-at-a-time: make the interfaces truly generic")
      Debugged-by: default avatarNathan Chancellor <nathan@kernel.org>
      Signed-off-by: default avatarNick Desaulniers <ndesaulniers@google.com>
      Acked-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      79e8328e
    • Hans de Goede's avatar
      wifi: brcmfmac: Fix field-spanning write in brcmf_scan_params_v2_to_v1() · 16e455a4
      Hans de Goede authored
      Using brcmfmac with 6.5-rc3 on a brcmfmac43241b4-sdio triggers
      a backtrace caused by the following field-spanning warning:
      
      memcpy: detected field-spanning write (size 120) of single field
        "&params_le->channel_list[0]" at
        drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:1072 (size 2)
      
      The driver still works after this warning. The warning was introduced by the
      new field-spanning write checks which were enabled recently.
      
      Fix this by replacing the channel_list[1] declaration at the end of
      the struct with a flexible array declaration.
      
      Most users of struct brcmf_scan_params_le calculate the size to alloc
      using the size of the non flex-array part of the struct + needed extra
      space, so they do not care about sizeof(struct brcmf_scan_params_le).
      
      brcmf_notify_escan_complete() however uses the struct on the stack,
      expecting there to be room for at least 1 entry in the channel-list
      to store the special -1 abort channel-id.
      
      To make this work use an anonymous union with a padding member
      added + the actual channel_list flexible array.
      
      Cc: Kees Cook <keescook@chromium.org>
      Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
      Reviewed-by: default avatarKees Cook <keescook@chromium.org>
      Reviewed-by: default avatarFranky Lin <franky.lin@broadcom.com>
      Signed-off-by: default avatarKalle Valo <kvalo@kernel.org>
      Link: https://lore.kernel.org/r/20230729140500.27892-1-hdegoede@redhat.com
      16e455a4
    • Benjamin Poirier's avatar
      vxlan: Fix nexthop hash size · 0756384f
      Benjamin Poirier authored
      The nexthop code expects a 31 bit hash, such as what is returned by
      fib_multipath_hash() and rt6_multipath_hash(). Passing the 32 bit hash
      returned by skb_get_hash() can lead to problems related to the fact that
      'int hash' is a negative number when the MSB is set.
      
      In the case of hash threshold nexthop groups, nexthop_select_path_hthr()
      will disproportionately select the first nexthop group entry. In the case
      of resilient nexthop groups, nexthop_select_path_res() may do an out of
      bounds access in nh_buckets[], for example:
          hash = -912054133
          num_nh_buckets = 2
          bucket_index = 65535
      
      which leads to the following panic:
      
      BUG: unable to handle page fault for address: ffffc900025910c8
      PGD 100000067 P4D 100000067 PUD 10026b067 PMD 0
      Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI
      CPU: 4 PID: 856 Comm: kworker/4:3 Not tainted 6.5.0-rc2+ #34
      Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
      Workqueue: ipv6_addrconf addrconf_dad_work
      RIP: 0010:nexthop_select_path+0x197/0xbf0
      Code: c1 e4 05 be 08 00 00 00 4c 8b 35 a4 14 7e 01 4e 8d 6c 25 00 4a 8d 7c 25 08 48 01 dd e8 c2 25 15 ff 49 8d 7d 08 e8 39 13 15 ff <4d> 89 75 08 48 89 ef e8 7d 12 15 ff 48 8b 5d 00 e8 14 55 2f 00 85
      RSP: 0018:ffff88810c36f260 EFLAGS: 00010246
      RAX: 0000000000000000 RBX: 00000000002000c0 RCX: ffffffffaf02dd77
      RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffc900025910c8
      RBP: ffffc900025910c0 R08: 0000000000000001 R09: fffff520004b2219
      R10: ffffc900025910cf R11: 31392d2068736168 R12: 00000000002000c0
      R13: ffffc900025910c0 R14: 00000000fffef608 R15: ffff88811840e900
      FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: ffffc900025910c8 CR3: 0000000129d00000 CR4: 0000000000750ee0
      PKRU: 55555554
      Call Trace:
       <TASK>
       ? __die+0x23/0x70
       ? page_fault_oops+0x1ee/0x5c0
       ? __pfx_is_prefetch.constprop.0+0x10/0x10
       ? __pfx_page_fault_oops+0x10/0x10
       ? search_bpf_extables+0xfe/0x1c0
       ? fixup_exception+0x3b/0x470
       ? exc_page_fault+0xf6/0x110
       ? asm_exc_page_fault+0x26/0x30
       ? nexthop_select_path+0x197/0xbf0
       ? nexthop_select_path+0x197/0xbf0
       ? lock_is_held_type+0xe7/0x140
       vxlan_xmit+0x5b2/0x2340
       ? __lock_acquire+0x92b/0x3370
       ? __pfx_vxlan_xmit+0x10/0x10
       ? __pfx___lock_acquire+0x10/0x10
       ? __pfx_register_lock_class+0x10/0x10
       ? skb_network_protocol+0xce/0x2d0
       ? dev_hard_start_xmit+0xca/0x350
       ? __pfx_vxlan_xmit+0x10/0x10
       dev_hard_start_xmit+0xca/0x350
       __dev_queue_xmit+0x513/0x1e20
       ? __pfx___dev_queue_xmit+0x10/0x10
       ? __pfx_lock_release+0x10/0x10
       ? mark_held_locks+0x44/0x90
       ? skb_push+0x4c/0x80
       ? eth_header+0x81/0xe0
       ? __pfx_eth_header+0x10/0x10
       ? neigh_resolve_output+0x215/0x310
       ? ip6_finish_output2+0x2ba/0xc90
       ip6_finish_output2+0x2ba/0xc90
       ? lock_release+0x236/0x3e0
       ? ip6_mtu+0xbb/0x240
       ? __pfx_ip6_finish_output2+0x10/0x10
       ? find_held_lock+0x83/0xa0
       ? lock_is_held_type+0xe7/0x140
       ip6_finish_output+0x1ee/0x780
       ip6_output+0x138/0x460
       ? __pfx_ip6_output+0x10/0x10
       ? __pfx___lock_acquire+0x10/0x10
       ? __pfx_ip6_finish_output+0x10/0x10
       NF_HOOK.constprop.0+0xc0/0x420
       ? __pfx_NF_HOOK.constprop.0+0x10/0x10
       ? ndisc_send_skb+0x2c0/0x960
       ? __pfx_lock_release+0x10/0x10
       ? __local_bh_enable_ip+0x93/0x110
       ? lock_is_held_type+0xe7/0x140
       ndisc_send_skb+0x4be/0x960
       ? __pfx_ndisc_send_skb+0x10/0x10
       ? mark_held_locks+0x65/0x90
       ? find_held_lock+0x83/0xa0
       ndisc_send_ns+0xb0/0x110
       ? __pfx_ndisc_send_ns+0x10/0x10
       addrconf_dad_work+0x631/0x8e0
       ? lock_acquire+0x180/0x3f0
       ? __pfx_addrconf_dad_work+0x10/0x10
       ? mark_held_locks+0x24/0x90
       process_one_work+0x582/0x9c0
       ? __pfx_process_one_work+0x10/0x10
       ? __pfx_do_raw_spin_lock+0x10/0x10
       ? mark_held_locks+0x24/0x90
       worker_thread+0x93/0x630
       ? __kthread_parkme+0xdc/0x100
       ? __pfx_worker_thread+0x10/0x10
       kthread+0x1a5/0x1e0
       ? __pfx_kthread+0x10/0x10
       ret_from_fork+0x34/0x60
       ? __pfx_kthread+0x10/0x10
       ret_from_fork_asm+0x1b/0x30
      RIP: 0000:0x0
      Code: Unable to access opcode bytes at 0xffffffffffffffd6.
      RSP: 0000:0000000000000000 EFLAGS: 00000000 ORIG_RAX: 0000000000000000
      RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
      RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
      RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
      R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
      R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
       </TASK>
      Modules linked in:
      CR2: ffffc900025910c8
      ---[ end trace 0000000000000000 ]---
      RIP: 0010:nexthop_select_path+0x197/0xbf0
      Code: c1 e4 05 be 08 00 00 00 4c 8b 35 a4 14 7e 01 4e 8d 6c 25 00 4a 8d 7c 25 08 48 01 dd e8 c2 25 15 ff 49 8d 7d 08 e8 39 13 15 ff <4d> 89 75 08 48 89 ef e8 7d 12 15 ff 48 8b 5d 00 e8 14 55 2f 00 85
      RSP: 0018:ffff88810c36f260 EFLAGS: 00010246
      RAX: 0000000000000000 RBX: 00000000002000c0 RCX: ffffffffaf02dd77
      RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffc900025910c8
      RBP: ffffc900025910c0 R08: 0000000000000001 R09: fffff520004b2219
      R10: ffffc900025910cf R11: 31392d2068736168 R12: 00000000002000c0
      R13: ffffc900025910c0 R14: 00000000fffef608 R15: ffff88811840e900
      FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: ffffffffffffffd6 CR3: 0000000129d00000 CR4: 0000000000750ee0
      PKRU: 55555554
      Kernel panic - not syncing: Fatal exception in interrupt
      Kernel Offset: 0x2ca00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
      ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
      
      Fix this problem by ensuring the MSB of hash is 0 using a right shift - the
      same approach used in fib_multipath_hash() and rt6_multipath_hash().
      
      Fixes: 1274e1cc ("vxlan: ecmp support for mac fdb entries")
      Signed-off-by: default avatarBenjamin Poirier <bpoirier@nvidia.com>
      Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
      Reviewed-by: default avatarSimon Horman <horms@kernel.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0756384f
    • Yue Haibing's avatar
      ip6mr: Fix skb_under_panic in ip6mr_cache_report() · 30e0191b
      Yue Haibing authored
      skbuff: skb_under_panic: text:ffffffff88771f69 len:56 put:-4
       head:ffff88805f86a800 data:ffff887f5f86a850 tail:0x88 end:0x2c0 dev:pim6reg
       ------------[ cut here ]------------
       kernel BUG at net/core/skbuff.c:192!
       invalid opcode: 0000 [#1] PREEMPT SMP KASAN
       CPU: 2 PID: 22968 Comm: kworker/2:11 Not tainted 6.5.0-rc3-00044-g0a8db05b #236
       Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
       Workqueue: ipv6_addrconf addrconf_dad_work
       RIP: 0010:skb_panic+0x152/0x1d0
       Call Trace:
        <TASK>
        skb_push+0xc4/0xe0
        ip6mr_cache_report+0xd69/0x19b0
        reg_vif_xmit+0x406/0x690
        dev_hard_start_xmit+0x17e/0x6e0
        __dev_queue_xmit+0x2d6a/0x3d20
        vlan_dev_hard_start_xmit+0x3ab/0x5c0
        dev_hard_start_xmit+0x17e/0x6e0
        __dev_queue_xmit+0x2d6a/0x3d20
        neigh_connected_output+0x3ed/0x570
        ip6_finish_output2+0x5b5/0x1950
        ip6_finish_output+0x693/0x11c0
        ip6_output+0x24b/0x880
        NF_HOOK.constprop.0+0xfd/0x530
        ndisc_send_skb+0x9db/0x1400
        ndisc_send_rs+0x12a/0x6c0
        addrconf_dad_completed+0x3c9/0xea0
        addrconf_dad_work+0x849/0x1420
        process_one_work+0xa22/0x16e0
        worker_thread+0x679/0x10c0
        ret_from_fork+0x28/0x60
        ret_from_fork_asm+0x11/0x20
      
      When setup a vlan device on dev pim6reg, DAD ns packet may sent on reg_vif_xmit().
      reg_vif_xmit()
          ip6mr_cache_report()
              skb_push(skb, -skb_network_offset(pkt));//skb_network_offset(pkt) is 4
      And skb_push declared as:
      	void *skb_push(struct sk_buff *skb, unsigned int len);
      		skb->data -= len;
      		//0xffff88805f86a84c - 0xfffffffc = 0xffff887f5f86a850
      skb->data is set to 0xffff887f5f86a850, which is invalid mem addr, lead to skb_push() fails.
      
      Fixes: 14fb64e1 ("[IPV6] MROUTE: Support PIM-SM (SSM).")
      Signed-off-by: default avatarYue Haibing <yuehaibing@huawei.com>
      Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      30e0191b