syzbot

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BUG: KMSAN: uninit-value in neigh_flush_dev+0x497/0xe20 net/core/neighbour.c:249
CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 4.18.0-rc5+ #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1e0 lib/dump_stack.c:113
 kmsan_report+0x195/0x2c0 mm/kmsan/kmsan.c:982
 __msan_warning+0x7d/0xe0 mm/kmsan/kmsan_instr.c:645
 neigh_flush_dev+0x497/0xe20 net/core/neighbour.c:249
 neigh_ifdown+0x94/0x8c0 net/core/neighbour.c:296
 rt6_disable_ip+0x9a3/0x9d0 net/ipv6/route.c:4069
 addrconf_ifdown+0x245/0x27b0 net/ipv6/addrconf.c:3649
 addrconf_notify+0x2dd/0x62b0 net/ipv6/addrconf.c:3574
 notifier_call_chain kernel/notifier.c:93 [inline]
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x13e/0x240 kernel/notifier.c:401
 call_netdevice_notifiers_info net/core/dev.c:1735 [inline]
 call_netdevice_notifiers net/core/dev.c:1753 [inline]
 rollback_registered_many+0x1510/0x2000 net/core/dev.c:7472
 unregister_netdevice_many net/core/dev.c:8577 [inline]
 default_device_exit_batch+0x709/0xc80 net/core/dev.c:9043
 ops_exit_list net/core/net_namespace.c:155 [inline]
 cleanup_net+0xbfb/0x1710 net/core/net_namespace.c:523
 process_one_work+0x1655/0x2000 kernel/workqueue.c:2153
 worker_thread+0x1136/0x2490 kernel/workqueue.c:2296
 kthread+0x473/0x4b0 kernel/kthread.c:247
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:415

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:181
 kmsan_kmalloc+0xa1/0x120 mm/kmsan/kmsan_hooks.c:91
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:100
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2720 [inline]
 __kmalloc_node_track_caller+0xb48/0x11d0 mm/slub.c:4353
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cb/0x9e0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:988 [inline]
 _sctp_make_chunk+0xf6/0x8f0 net/sctp/sm_make_chunk.c:1402
 sctp_make_control net/sctp/sm_make_chunk.c:1449 [inline]
 sctp_make_abort+0xf7/0x720 net/sctp/sm_make_chunk.c:961
 sctp_sf_tabort_8_4_8+0x158/0x7f0 net/sctp/sm_statefuns.c:3381
 sctp_sf_ootb+0xc8d/0xd40 net/sctp/sm_statefuns.c:3602
 sctp_do_sm+0x2d9/0x9fe0 net/sctp/sm_sideeffect.c:1188
 sctp_endpoint_bh_rcv+0xd55/0x1040 net/sctp/endpointola.c:456
 sctp_inq_push+0x314/0x460 net/sctp/inqueue.c:95
 sctp_rcv+0x48d2/0x52c0 net/sctp/input.c:267
 ip_local_deliver_finish+0x851/0xf00 net/ipv4/ip_input.c:215
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip_local_deliver+0x455/0x510 net/ipv4/ip_input.c:256
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish+0xa1b/0x1d10 net/ipv4/ip_input.c:396
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip_rcv+0x12d4/0x14f0 net/ipv4/ip_input.c:492
 __netif_receive_skb_core+0x4a7a/0x4fc0 net/core/dev.c:4628
 __netif_receive_skb net/core/dev.c:4693 [inline]
 process_backlog+0x664/0xe60 net/core/dev.c:5373
 napi_poll net/core/dev.c:5771 [inline]
 net_rx_action+0x799/0x1ae0 net/core/dev.c:5837
 __do_softirq+0x55f/0x934 kernel/softirq.c:288
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