syzbot

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BUG: KMSAN: uninit-value in ip6_finish_output2+0x395/0x2280 net/ipv6/ip6_output.c:70
CPU: 0 PID: 21232 Comm: syz-executor6 Not tainted 4.18.0-rc4+ #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __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
 ip6_finish_output2+0x395/0x2280 net/ipv6/ip6_output.c:70
 ip6_fragment+0x472f/0x5240 net/ipv6/ip6_output.c:843
 ip6_finish_output+0xa14/0xbb0 net/ipv6/ip6_output.c:152
 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]
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip6_xmit+0x2211/0x2570 net/ipv6/ip6_output.c:277
 sctp_v6_xmit+0x48d/0x570 net/sctp/ipv6.c:225
 sctp_packet_transmit+0x42b3/0x4760 net/sctp/output.c:650
 sctp_packet_singleton net/sctp/outqueue.c:791 [inline]
 sctp_outq_flush_ctrl net/sctp/outqueue.c:922 [inline]
 sctp_outq_flush+0x9df/0x6090 net/sctp/outqueue.c:1203
 sctp_outq_uncork+0xd2/0xf0 net/sctp/outqueue.c:776
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1349 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline]
 sctp_do_sm+0x4a30/0x9fe0 net/sctp/sm_sideeffect.c:1191
 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
 sctp6_rcv+0x41/0x70 net/sctp/ipv6.c:1045
 ip6_input_finish+0x1353/0x22b0 net/ipv6/ip6_input.c:284
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip6_input+0x2a1/0x340 net/ipv6/ip6_input.c:327
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x498/0x6e0 net/ipv6/ip6_input.c:71
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ipv6_rcv+0x1ea9/0x2250 net/ipv6/ip6_input.c:208
 __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
 do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1054
 </IRQ>
 do_softirq kernel/softirq.c:332 [inline]
 __local_bh_enable_ip+0x134/0x170 kernel/softirq.c:185
 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:725 [inline]
 ip6_finish_output2+0x1e23/0x2280 net/ipv6/ip6_output.c:121
 ip6_fragment+0x472f/0x5240 net/ipv6/ip6_output.c:843
 ip6_finish_output+0xa14/0xbb0 net/ipv6/ip6_output.c:152
 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]
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip6_xmit+0x2211/0x2570 net/ipv6/ip6_output.c:277
 sctp_v6_xmit+0x48d/0x570 net/sctp/ipv6.c:225
 sctp_packet_transmit+0x42b3/0x4760 net/sctp/output.c:650
 sctp_packet_singleton net/sctp/outqueue.c:791 [inline]
 sctp_outq_flush_ctrl net/sctp/outqueue.c:922 [inline]
 sctp_outq_flush+0x9df/0x6090 net/sctp/outqueue.c:1203
 sctp_outq_uncork+0xd2/0xf0 net/sctp/outqueue.c:776
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1820 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline]
 sctp_do_sm+0x9919/0x9fe0 net/sctp/sm_sideeffect.c:1191
 sctp_primitive_ASSOCIATE+0x172/0x1a0 net/sctp/primitive.c:88
 sctp_sendmsg_to_asoc+0x195a/0x2890 net/sctp/socket.c:1936
 sctp_sendmsg+0x3f3e/0x6500 net/sctp/socket.c:2124
 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_sendto+0x798/0x8e0 net/socket.c:1797
 __do_sys_sendto net/socket.c:1809 [inline]
 __se_sys_sendto net/socket.c:1805 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1805
 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:00007f5b18ccec68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5b18ccf6d4 RCX: 0000000000455e29
RDX: 0000000000000001 RSI: 000000002087dffe RDI: 0000000000000016
RBP: 000000000072bea0 R08: 000000002005ffe4 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c14fe R14: 00000000004d1a20 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 include/linux/skbuff.h:3378 [inline]
 ip6_fragment+0x4214/0x5240 net/ipv6/ip6_output.c:811
 ip6_finish_output+0xa14/0xbb0 net/ipv6/ip6_output.c:152
 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]
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip6_xmit+0x2211/0x2570 net/ipv6/ip6_output.c:277
 sctp_v6_xmit+0x48d/0x570 net/sctp/ipv6.c:225
 sctp_packet_transmit+0x42b3/0x4760 net/sctp/output.c:650
 sctp_packet_singleton net/sctp/outqueue.c:791 [inline]
 sctp_outq_flush_ctrl net/sctp/outqueue.c:922 [inline]
 sctp_outq_flush+0x9df/0x6090 net/sctp/outqueue.c:1203
 sctp_outq_uncork+0xd2/0xf0 net/sctp/outqueue.c:776
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1349 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline]
 sctp_do_sm+0x4a30/0x9fe0 net/sctp/sm_sideeffect.c:1191
 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
 sctp6_rcv+0x41/0x70 net/sctp/ipv6.c:1045
 ip6_input_finish+0x1353/0x22b0 net/ipv6/ip6_input.c:284
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip6_input+0x2a1/0x340 net/ipv6/ip6_input.c:327
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x498/0x6e0 net/ipv6/ip6_input.c:71
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ipv6_rcv+0x1ea9/0x2250 net/ipv6/ip6_input.c:208
 __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

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_packet_transmit+0x472/0x4760 net/sctp/output.c:593
 sctp_packet_singleton net/sctp/outqueue.c:791 [inline]
 sctp_outq_flush_ctrl net/sctp/outqueue.c:922 [inline]
 sctp_outq_flush+0x9df/0x6090 net/sctp/outqueue.c:1203
 sctp_outq_uncork+0xd2/0xf0 net/sctp/outqueue.c:776
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1349 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline]
 sctp_do_sm+0x4a30/0x9fe0 net/sctp/sm_sideeffect.c:1191
 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
 sctp6_rcv+0x41/0x70 net/sctp/ipv6.c:1045
 ip6_input_finish+0x1353/0x22b0 net/ipv6/ip6_input.c:284
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip6_input+0x2a1/0x340 net/ipv6/ip6_input.c:327
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x498/0x6e0 net/ipv6/ip6_input.c:71
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ipv6_rcv+0x1ea9/0x2250 net/ipv6/ip6_input.c:208
 __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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