==================================================================
BUG: KMSAN: uninit-value in ipv6_ext_hdr net/ipv6/exthdrs_core.c:17 [inline]
BUG: KMSAN: uninit-value in ipv6_skip_exthdr+0x156/0x910 net/ipv6/exthdrs_core.c:78
CPU: 1 PID: 16006 Comm: syz-executor3 Not tainted 4.18.0-rc4+ #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
 __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:990
 __msan_warning_32+0x7d/0xe0 mm/kmsan/kmsan_instr.c:640
 ipv6_ext_hdr net/ipv6/exthdrs_core.c:17 [inline]
 ipv6_skip_exthdr+0x156/0x910 net/ipv6/exthdrs_core.c:78
 ipv6_get_l4proto+0x1be/0x2f0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:83
 nf_conntrack_in+0x54a/0x2070 net/netfilter/nf_conntrack_core.c:1388
 ipv6_conntrack_local+0xc3/0xf0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:179
 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]
 ___sys_sendmsg+0xed9/0x1350 net/socket.c:2125
 __sys_sendmsg net/socket.c:2163 [inline]
 __do_sys_sendmsg net/socket.c:2172 [inline]
 __se_sys_sendmsg net/socket.c:2170 [inline]
 __x64_sys_sendmsg+0x3b0/0x520 net/socket.c:2170
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x455e29
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:00007f0278b95c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0278b966d4 RCX: 0000000000455e29
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c1165 R14: 00000000004d15d0 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:271 [inline]
 kmsan_internal_chain_origin+0x13c/0x240 mm/kmsan/kmsan.c:581
 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:425
 __msan_memcpy+0xe7/0x150 mm/kmsan/kmsan_instr.c:432
 skb_copy_from_linear_data_offset include/linux/skbuff.h:3385 [inline]
 skb_copy_bits+0x1f9/0xd80 net/core/skbuff.c:2038
 ipv6_get_l4proto+0x105/0x2f0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:78
 nf_conntrack_in+0x54a/0x2070 net/netfilter/nf_conntrack_core.c:1388
 ipv6_conntrack_local+0xc3/0xf0 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:179
 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]
 ___sys_sendmsg+0xed9/0x1350 net/socket.c:2125
 __sys_sendmsg net/socket.c:2163 [inline]
 __do_sys_sendmsg net/socket.c:2172 [inline]
 __se_sys_sendmsg net/socket.c:2170 [inline]
 __x64_sys_sendmsg+0x3b0/0x520 net/socket.c:2170
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:271 [inline]
 kmsan_internal_chain_origin+0x13c/0x240 mm/kmsan/kmsan.c:581
 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:425
 kmsan_memmove_origins+0x9/0x10 mm/kmsan/kmsan.c:480
 __msan_memmove+0xe7/0x150 mm/kmsan/kmsan_instr.c:381
 nf_ct_frag6_reasm net/ipv6/netfilter/nf_conntrack_reasm.c:432 [inline]
 nf_ct_frag6_gather+0x436a/0x5870 net/ipv6/netfilter/nf_conntrack_reasm.c:586
 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]
 ___sys_sendmsg+0xed9/0x1350 net/socket.c:2125
 __sys_sendmsg net/socket.c:2163 [inline]
 __do_sys_sendmsg net/socket.c:2172 [inline]
 __se_sys_sendmsg net/socket.c:2170 [inline]
 __x64_sys_sendmsg+0x3b0/0x520 net/socket.c:2170
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

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_large+0x7c/0xe0 mm/kmsan/kmsan_hooks.c:128
 kmalloc_large_node_hook mm/slub.c:1352 [inline]
 kmalloc_large_node mm/slub.c:3799 [inline]
 __kmalloc_node_track_caller+0xf53/0x11d0 mm/slub.c:4339
 __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]
 __ip6_append_data+0x3c45/0x5320 net/ipv6/ip6_output.c:1427
 ip6_append_data+0x40e/0x6b0 net/ipv6/ip6_output.c:1590
 rawv6_sendmsg+0x2909/0x5410 net/ipv6/raw.c:928
 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]
 ___sys_sendmsg+0xed9/0x1350 net/socket.c:2125
 __sys_sendmsg net/socket.c:2163 [inline]
 __do_sys_sendmsg net/socket.c:2172 [inline]
 __se_sys_sendmsg net/socket.c:2170 [inline]
 __x64_sys_sendmsg+0x3b0/0x520 net/socket.c:2170
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================