syzbot

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BUG: KMSAN: uninit-value in ip6_tnl_parse_tlv_enc_lim+0x83f/0xa90 net/ipv6/ip6_tunnel.c:420
CPU: 0 PID: 12567 Comm: syz-executor2 Not tainted 4.18.0-rc4+ #27
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+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
 ip6_tnl_parse_tlv_enc_lim+0x83f/0xa90 net/ipv6/ip6_tunnel.c:420
 ip6ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1333 [inline]
 ip6_tnl_start_xmit+0x9f3/0x2120 net/ipv6/ip6_tunnel.c:1397
 __netdev_start_xmit include/linux/netdevice.h:4148 [inline]
 netdev_start_xmit include/linux/netdevice.h:4157 [inline]
 xmit_one net/core/dev.c:3034 [inline]
 dev_hard_start_xmit+0x60f/0xcc0 net/core/dev.c:3050
 __dev_queue_xmit+0x3060/0x3c70 net/core/dev.c:3569
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3602
 neigh_direct_output+0x42/0x50 net/core/neighbour.c:1403
 neigh_output include/net/neighbour.h:483 [inline]
 ip6_finish_output2+0x1e0d/0x2280 net/ipv6/ip6_output.c:120
 ip6_finish_output+0xaf0/0xbb0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:276 [inline]
 ip6_output+0x5c5/0x710 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:444 [inline]
 ip6_local_out+0x164/0x1d0 net/ipv6/output_core.c:176
 ip6_send_skb net/ipv6/ip6_output.c:1696 [inline]
 ip6_push_pending_frames+0x218/0x4d0 net/ipv6/ip6_output.c:1716
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x45f0/0x5410 net/ipv6/raw.c:935
 inet_sendmsg+0x3fc/0x760 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg net/socket.c:651 [inline]
 sock_write_iter+0x408/0x4d0 net/socket.c:920
 call_write_iter include/linux/fs.h:1793 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x87e/0xb90 fs/read_write.c:487
 vfs_write+0x467/0x8c0 fs/read_write.c:549
 ksys_write fs/read_write.c:598 [inline]
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x1cf/0x400 fs/read_write.c:607
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x455ab9
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007f4c8c294c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4c8c2956d4 RCX: 0000000000455ab9
RDX: 000000000000001c RSI: 0000000020000080 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c2c19 R14: 00000000004d4c08 R15: 0000000000000000

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]
 pskb_expand_head+0x21d/0x1a70 net/core/skbuff.c:1462
 __pskb_pull_tail+0x1e4/0x2300 net/core/skbuff.c:1896
 pskb_may_pull include/linux/skbuff.h:2118 [inline]
 nf_ct_frag6_gather+0x1087/0x5870 net/ipv6/netfilter/nf_conntrack_reasm.c:554
 ipv6_defrag+0x501/0x5c0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:71
 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline]
 nf_hook_slow+0x15d/0x3e0 net/netfilter/core.c:511
 nf_hook include/linux/netfilter.h:242 [inline]
 __ip6_local_out+0x64c/0x770 net/ipv6/output_core.c:164
 ip6_local_out+0xa4/0x1d0 net/ipv6/output_core.c:174
 ip6_send_skb net/ipv6/ip6_output.c:1696 [inline]
 ip6_push_pending_frames+0x218/0x4d0 net/ipv6/ip6_output.c:1716
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x45f0/0x5410 net/ipv6/raw.c:935
 inet_sendmsg+0x3fc/0x760 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg net/socket.c:651 [inline]
 sock_write_iter+0x408/0x4d0 net/socket.c:920
 call_write_iter include/linux/fs.h:1793 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x87e/0xb90 fs/read_write.c:487
 vfs_write+0x467/0x8c0 fs/read_write.c:549
 ksys_write fs/read_write.c:598 [inline]
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x1cf/0x400 fs/read_write.c:607
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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