syzbot

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BUG: KMSAN: uninit-value in ipv6_rcv+0xea9/0x20d0 net/ipv6/ip6_input.c:118
CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 4.18.0-rc8+ #34
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x17c/0x1c0 lib/dump_stack.c:113
 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:982
 __msan_warning+0x70/0xc0 mm/kmsan/kmsan_instr.c:645
 ipv6_rcv+0xea9/0x20d0 net/ipv6/ip6_input.c:118
 __netif_receive_skb_core+0x4511/0x49d0 net/core/dev.c:4628
 __netif_receive_skb net/core/dev.c:4693 [inline]
 process_backlog+0x5f1/0xd80 net/core/dev.c:5373
 napi_poll net/core/dev.c:5771 [inline]
 net_rx_action+0x723/0x19d0 net/core/dev.c:5837
 __do_softirq+0x582/0x969 kernel/softirq.c:292
 run_ksoftirqd+0x24/0x40 kernel/softirq.c:656
 smpboot_thread_fn+0x4ad/0x9b0 kernel/smpboot.c:164
 kthread+0x44d/0x480 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+0xb8/0x1b0 mm/kmsan/kmsan.c:181
 kmsan_kmalloc+0x98/0x100 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+0xb4c/0x11d0 mm/slub.c:4353
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2ce/0x9b0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:988 [inline]
 alloc_skb_with_frags+0x1d0/0xac0 net/core/skbuff.c:5272
 sock_alloc_send_pskb+0xb47/0x1120 net/core/sock.c:2095
 unix_dgram_sendmsg+0xd77/0x36a0 net/unix/af_unix.c:1672
 sock_sendmsg_nosec net/socket.c:642 [inline]
 sock_sendmsg net/socket.c:652 [inline]
 __sys_sendto+0x6a3/0x7c0 net/socket.c:1798
 __do_sys_sendto net/socket.c:1810 [inline]
 __se_sys_sendto net/socket.c:1806 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1806
 do_syscall_64+0x15b/0x220 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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