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BUG: KMSAN: uninit-value in ip6_parse_tlv+0x8a2/0xc90 net/ipv6/exthdrs.c:172
CPU: 1 PID: 8649 Comm: syz-executor7 Not tainted 4.16.0+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
 ip6_parse_tlv+0x8a2/0xc90 net/ipv6/exthdrs.c:172
 ipv6_destopt_rcv+0x525/0xde0 net/ipv6/exthdrs.c:310
 ip6_input_finish+0xa62/0x2110 net/ipv6/ip6_input.c:284
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip6_input net/ipv6/ip6_input.c:327 [inline]
 ip6_mc_input+0x697/0x740 net/ipv6/ip6_input.c:404
 dst_input include/net/dst.h:449 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:71 [inline]
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ipv6_rcv+0x20ec/0x26d0 net/ipv6/ip6_input.c:208
 __netif_receive_skb_core+0x47cf/0x4a80 net/core/dev.c:4562
 __netif_receive_skb net/core/dev.c:4627 [inline]
 process_backlog+0x62d/0xe20 net/core/dev.c:5307
 napi_poll net/core/dev.c:5705 [inline]
 net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
 __do_softirq+0x56d/0x93d kernel/softirq.c:285
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
 </IRQ>
 do_softirq+0xb6/0xf0 kernel/softirq.c:329
 netif_rx_ni net/core/dev.c:4192 [inline]
 dev_loopback_xmit+0x8b0/0x900 net/core/dev.c:3320
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip6_finish_output2+0x5e6/0x1f20 net/ipv6/ip6_output.c:84
 ip6_finish_output+0xb3f/0xc00 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:277 [inline]
 ip6_output+0x597/0x6c0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:443 [inline]
 ip6_local_out+0x573/0x640 net/ipv6/output_core.c:176
 ip6_send_skb net/ipv6/ip6_output.c:1682 [inline]
 ip6_push_pending_frames+0x218/0x4d0 net/ipv6/ip6_output.c:1702
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x4500/0x4cc0 net/ipv6/raw.c:935
 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 SYSC_sendto+0x6c3/0x7e0 net/socket.c:1747
 SyS_sendto+0x8a/0xb0 net/socket.c:1715
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455319
RSP: 002b:00007ff297ec0c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007ff297ec16d4 RCX: 0000000000455319
RDX: 0000000000000000 RSI: 0000000020001ffe RDI: 0000000000000013
RBP: 000000000072bf58 R08: 0000000020003000 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004f8 R14: 00000000006fa7e0 R15: 0000000000000001

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
 slab_post_alloc_hook mm/slab.h:445 [inline]
 slab_alloc_node mm/slub.c:2737 [inline]
 __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:984 [inline]
 alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
 sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2102
 __ip6_append_data+0x3387/0x4bb0 net/ipv6/ip6_output.c:1414
 ip6_append_data+0x40e/0x6b0 net/ipv6/ip6_output.c:1576
 rawv6_sendmsg+0x2787/0x4cc0 net/ipv6/raw.c:928
 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 SYSC_sendto+0x6c3/0x7e0 net/socket.c:1747
 SyS_sendto+0x8a/0xb0 net/socket.c:1715
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
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